What about early Weatherby Mark V rifles in .300 Wby Mag? They evidently only had 1:12 inch twist rates. How did they handle the 200 and 220-grain bullets?
@@DJones476 good question. Every bullet needs to rotate at a certain spin rate for stability. This spin rate is a function of the rifling twist rate (faster twist rates equal a faster spin rate) and bullet velocity (faster velocity equals faster spin rate). You can calculate the spin rate of a bullet by multiplying the muzzle velocity times 720 and then dividing that number by the barrel twist rate. For instance, a bullet fired at 3,200fps from a rifle with a 1:12 twist rate is spinning at 192,000 RPM. A bullet fired at 2,666fps from a rifle with a faster 1:10 twist rate has the exact spin rate. With that in mind, a very high velocity loading like the 300 Weatherby can get by with a slower rifling twist rate. Plus, I'll bet those older 200gr and 220gr 300 Weatherby loadings that worked with a 1:12 twist rate were pretty basic round or pointed bullets that weren't especially long or sleek compared to the really high BC stuff we have today like the ELD-X or AccuBond Long Range, and therefore didn't need as fast of a spin rate for stability. Make sense?
@@Thebiggamehuntingblog 192,000 RPM, Wow, that's almost as fast as my 318 Detroit was turning coming down the Grapevine in fourth gear after I lost my brakes! And any dude that don't find bullets and twist rates worth a look probably also puts water in his whiskey.
The topic that needs to be discussed with a big channel like you is how slow twist rate guns can shoot long high b.c. bullets. For example my 1in10 twist 270 Win shoots the 165 ABLR incredibly accurate. I have tested it out to 800 yards. The 270 Win will also shoot the 170 gr EOL extremely well. I also have a couple of friends with 270 WSM rifles that shoot the 165 ABLR at much lower elevation than me with great success.
Wrong. There is a center of pressure vs center of gravity issue. Its nothing to do with length. Think about archery arrows. They dont fall end over end when fired. They're long and light. Revise your belief structure with science. Go to Hornady youtube and look for internal ballistics, bullet construction, and other similar episodes. They have actual ballistic engineers on their show.
@neglectfulsausage7689 I have video proof on my channel of shooting high b.c. bullets in slower twist rate guns. Just recently I showed a 1in9.5 7mm-08 getting sub Half MOA with the 180 gr ELD-M. Speaking of Hornady... did you know they themselves admit you don't need the faster twist rate in their reloading book?
Ballistics is such an interesting science. Bullet shape for and aft, density, pressure, combustion rates, twist rates, muzzle crown. I worry for anyone who wouldn't find it interesting.
Most cartridge designs have been around for decades; the loads are tried and true (and safe). Here's a novel idea! Instead of trying to fit a square peg in a round hole, why not establish a goal for speed or accuracy and find a standard barrel, cartridge, bullet and load that do so without unacceptable risk? For some reason sites like this one seem to be a magnet for guys who want to be the first to break a record. I'm glad that Mr Spomer preaches a safe and sane approach.
I think that the "old Kynoch bullets" and "round nose" are the pertinent points. The Guest also mentioned that the PH switched from old-style round nosed bullet to flat nosed. This is very important. A large flat nose ( 65+% diameter is often mentioned) tends to travel through tissue in a straight line. Round nose designs and those with very small flat noses are much more likely to yaw. If you look at high-speed photos, almost many bullets yaw significantly immediately after leaving the muzzle. It often takes well over 100 yards for a bullet to "go to sleep". The flat-based bullets favored by short-range benchrest shooters yaw less, but have lower BC, which is why they are only used for relatively short ranges. FWIW, in WWI, the British noted that their 303 bullets penetrated sandbags best at about 200 yards. This implies significant yaw up till that point. It is of note that "fleet yaw" in military 5.56x45 ammo was noted as an issue for its lethality. For the FMJ bullets that depend on yawing for damaging tissue, a very small yaw of several degrees turned out to be very important. Bullets that hit the target perfectly end-on tended to punch straight through and cause little damage. A lot of work has been done to ensure that modern military bullets will yaw rapidly.
That is the reason why. In África they began yesting the Meplat point. Beca use, Round nos hitting heavy bone tend to to deform and Tumble... John said it... "very old"
Lapua has some helpful content on their website on the matter. The issue with an over stabilized bullet is that it is flying nose up and not in line with the trajectory. I think this explains nicely the anecdotal penetration issue as the bullet impacts with a cross section rather than the pointy end
I think you've explained it nicely, Nikos. But I would add it could also be nose down at impact because the spiraling nose has yaw (left to right) and pitch (up and down) around the bullet axis. Who can predict at what specific tilt the nose is upon landing? This is why flat nosed bullets are famous for straight line penetration. Less likely to present a degree of cross section/flank for deflection.
@@RonSpomerOutdoors the wobbling would be dynamic stability, or the lack thereof 😁. From what I read this should only be really relevant past 600 yards. Do you think it is a factor on very short distances as well?
Sorry guys, the wobble happens on virtually all shots; it’s the variation in initial wobble magnitude & direction that causes groups to non-zero in size. The wobble DOESN’T mean the bullet is “unstable” unless the wobble grows with range, then it’s said to be “dynamically unstable “.
Mr Siewert is a ballistics expert and knows more than any of us. Many bullets wobble a bit at launch and few have "gone to sleep" at the short distances mentioned in this video. I suspect that the important thing is that the longer, flat-nosed bullets that the PH switched to just tend to travel in a straighter line through tissue than the old round nosed ones.
In testing for the 8.6 blackout, they did test 1:1 twist rates. They only reason they settled on 1:3 was because of barrel life, not terminal performance. They found 1:1 to be better.
Source please? The 8.6 Blackout is an unusual case since they are traveling slowly (subsonic) and depend on wide expansion to kill game. The fast twist seems to help some bullets, especially monolithic (copper) ones to expand widely and damage more tissue if it hits at relatively low velocity. Broadhead arrows use this principle as well. Such fast spin will cause normal cup and core bullets to fly apart at typical rifle speeds of over 2000 fps.
From the mouth of the creator of the blackout. He said that bullet manufactures would have trouble stopping bullets from flying apart the moment they exit the barrel. Barrel life wasn't the issue. He was recently on Demo Ranch and said this. 1:3 was the sweet spot where off the shelf bullets wouldn't fly apart.
@@shperax That makes sense. I know that just increasing the twist from 1:7" to 1:5" in the 300 Blackout caused some bullets to expand as soon as they left the barrel.... and that was for bullets designed specifically for the cartridge.
I have read but not confirmed that when 8.6 BLK was being considered for SAAMI approval, Hornady objected to 1:3 twist and wanted 1:5. My guess is that has to do with bullet design/manufacture.
Thinking about this, the bullet spin and the expanding gases pushing on bullet as it leaves the rifled barrels need to be tuned to prevent spin yawing. Having a precise or geometric balance barrel crown would also help by allowing the bullet complete circumference area lose contact with barrel instantaneously and the expanding gases exiting the barrel uniformly flow around the bullet as it leaves the barrel.
A common problem with the old Kynoch style solids is fish tailing which can cause a tumbling. Especially at close range and high velocity. Modern monolithic and modern flat point very sturdy bullets like Hornaday DGS don't do this. Riveting is also a problem in those old ones. The PMP 286gr. Brass solids were developed specifically for this issue for elephant culling in the Kruger park
Was the cartridge hand loaded? Was the bullet defective? Was it seated off-center in the neck? Was it off-center in the throat? How much free-bore did the barrel have? What was the throat diameter ratio?
I have had only one gun that seemed to have too high a twist rate, which was a puzzle at the time. I have a Dan Wesson 44 mag with an 8 inch barrel with a compensator with some copper plated bullets which was very accurate out to 25 Yds, but afterwards the bullets seemed to go wild. I also noted that when I did hit the target the bullet hole had a tail on it. The jacket seemed to be spinning off the bullet and making it unstable. Sometimes also keyholing. Luckily the Dan Wesson is designed to easily change barrels, and changing the barrel seemed to solve the problem. I suspect that the 8 inch barrel was meant for some specialty bullets. That side ported barrel also had huge muzzle blast, the shooters near me usually moved. Although as far as needing a powerful rifle to kil elephants. I beleive kiliminjaro bell took several hundred elephants with 7x57 but was an expert on bullet placement.
Hi Ron, love your show and testing my knowledge often and coming away with a new perspective that generally makes me feel I am better informed after your show than before. Why is twist rate so susceptible to different schools of thought? I used to believe it was about the mass of the projectile that required a faster twist rate to stabilize a heavier bullet. Listening to you for some time now and some additional research reveals that it’s the length of the projectile. Now your guest expert explains that it’s the weight that matters. Color me officially confused. Surely there must be empirical data to support one or the other. What should we believe? Thank you for keeping my knowledge ego in-check. Best, John B
Winchester, I suspect much of the confusion results from decades of everyone believing and repeating that heavier bullet required faster twist to stabilize. This was true once but only because heavier bullets were LONGER by necessity. Most ammo makers set things up with rifling twist adequate to stabilize the heaviest (longest) bullets they wanted their cartridges to shoot. Thus, the U.S. Military set up the 30-06 with 10" twist to stabilize their 220-gr. round nose. A 220-gr. Barnes TTSX (if there even is such a thing) would not stabilize even though the weight is the same because the length is not! There may be some subtle weight contributions I'm not aware of but John was that might be at play, but all my research shows length, length, and length.
This makes sense I shoot a 8x57 and it likes the heavy bullets because it was developed for 196 grain bullets 180s shoot nice groups while 150s open the groups out and old 120 more so.
This is probably due to the wear in the barrel throat. Lighter bullets have a shorter shank and are more likely to be slightly sideways as they travel through the barrel. An old trick for used barrels was to choose a bullet with the longest full-diameter shank. This was often a heavy bullet. One of the features of a "match chamber", or modern chambers like the PRC and Creedmoor series, is to provide a long section of very tight freebore to ensure that the bullet is properly aligned as it enters the rifling. These days, the clearance is often half a thousandth of an inch in that freebore section to give an idea of what is now common.
I've been loading for 40 years for hunting and competition. I've shot out the barrel in a .300 Weatherby,, it was used for a lot of long range shooting. Barrels are like tires on your car in a sense. It all depends on how you use it. I often hunt with a 54 year old 7mm Magnum, and a 60 year old .300 H&H, as well as a 70 year old .375 H&H. You take care of then, and don't abuse them, they'll out last you. After loading thousands of rounds over the years, I can honestly say I've had zero issues as far as the belt. Belted or beltless, makes no difference to me.
Yea theres a lot of factors in this weight shape powder and twist rate of ammo its why u test to see what ammo works best for ur guns and me in my 30-06 i oil my barrel before going out to get a smooth straight long range shots.
I bought a tikka t3x in .243. I wanted to shoot deer/pronghorn with 100gr norma, Hornaday soft point ammo. At 100yds, I was moa but at 300 yds, I was almost off paper - even 90gr eld-x. The tikka comes with 1 in 10 twist (the original 1955 twist rate). After a lot frustration and ammo, I put a new pac nor barrel on the gun with a 1 in 8 twist and the problems went away. Could it be that manufacturers need to rethink twist rate with all the new bullet designs?
I watched some football games where the quarter back made a long pass, the ball had similar behavior mentioned by you guys, where maybe within 10 feet when the ball left the thrower’s hand it looked not stabilized and flew a bit wonky, but as it travelled further it became more stable and caught by the guy in the front. Kinda make sense as mentioned in the video where the 375hh may over stabilize in a short distance and do not perform as expected, but it reaches it’s best performance in a mid to longer distance.
Does that mean it has to do with were the twist is being applied? So if the area that engages the rifling is not center of mass it would pitch and yaw initially but settled into stability
I think you're onto it, awsomedude. The center of gravity in the bullet and its relationship to the center of pressure are at play. @@awsomedude12345678
@justenzo928 I just watched over a 100 of NFL longest passes in slow motion. My eyeballs say you are full of adam schitt. Every football throw that started out wobbling stayed just as wobbling until they were caught. Some started fairly stabile became more wobbly after reaching the peak of the parabolic arc and became less stabile on the latter half of their flight. What you said is complete B.S. The ignorant, story that bullets and footballs go to sleep, is a B.S. made up fairy tale. In physics there is some thing called summation of forces. The net force is what has meaning. "May the the force be with you" is another Hollywood fake fairly tale. The NET force is the summation of forces and the one that has meaning. People who say a top that starts out wobbling goes to sleep and starts spinning true, are not properly summing the forces when comparing that to bullet or football. If you drop a wobbling spinning top off the Empire state building it will stay wobbling until it is acted upon another force that causes it to resist wobbling. Like letting one end of the top come in contact with the ground which is not moving in relation to spinning top. The force of the ground acting on one end of the top is what forces it to stop wobbling,,,,,,, NOT because it goes to sleep or some other ignorant theory!
I like your first question Ron ,,,,, so this is a twist rate problem ,,, if happened as described could have been a number of things caused it ,,,, referring to the bullet on the elephant tongue
The pressure drops quickly after the bullet leaves the case. The velocity won't be affected much because it is countered by the round remaining in the barrel a fraction longer and gets pushed more because it is pressure over time.
You're thinking about it correctly, but you also have to take into account what that increase in pressure does to the burn rate. It's impossible to determine through mere speculation. However, it is safe to say, based on simple physics, that it requires more energy to push a bullet to a given speed with a faster twist than it takes to push the same bullet to the same speed with a slower twist. What this looks like in a side by side comparison real life experiment might be strange though, since the different factors could change the rate at which the powder delivers its energy.
The difference in energy required w/fast twist vs slow twist rifling is on the order of 0.05% of the total energy available. You’d get more swing in peak pressure from barrel-barrel differences in bore dimensions.
Is there a chance that there is a variance in projectile velocity large enough to cause this stability issue?? Idk, but that makes sense. But, also, there surely would be a noticeable difference in recoil that would be a tip-off to that being the reason.
These issues of destabilization can be caused by damage to the mouth of the firearm. A chipped muzzle can cause pressure to exit earlier on one side and push the bullet out of balance. This could perhaps, as you say, correct itself in flight after a certain number of yards. That is one issue that I do not hear mentioned in your conversation. The old .505 Giggs's spitting hole may have been damage in its long travels.
I watched a Reloading video about the .22 Creedmoor where long heavy bullets were properly stabilized with fast twist rates, but lighter shorter bullets were going into the target sideways and breaking apart with those same twist rates. We all know that the .22 Creed makes some very high velocities with lighter bullets. I came away from that with a better understanding about too fast twist rates with lighter bullets for caliber and cartridge.
BINGO! on bullet "length" being critical for a given twist rate. I first picked up on the "stability" issue shooting military matches using the Steyr AUG in 5.56 NATO, which uses a 62grain, composite cored bullet. (SS-109 / M855 / F1, etc.) The STANDARD twist for those rifles is a very fast 1:7" twist. This is NOT necessarily needed to stabilize the "ball" projectile, but to tame the ludicrously long L-110 / M856 TRACER bullet. The "SAW / LMG" companion, the FN Minimi / M249, had the same twist, stamped right there on the barrel, specifically to stabilize the tracer ammo. So, what was the "tell" on "over-stabilization"? Longer ranges. We were noticing weird group "blowout" at 500 yards. This from rifles that would put ten rounds into a palm-sized group at 300. The exception was that troops with the 16" CARBINE barrels were sweeping the pool at 500. Enter the concept of "over-stabilization". A the bullet leaves the muzzle, it is (hopefully) spinning. However, there is no such thing as a "perfect" barrel (or crown" and certainly no "perfect bullets. As noted in this video, bullets are KNOWN to "spiral" around the trajectory. The "boffin" term is "precession". The bullet will, eventually start to rotate around its OWN centre of mass, which may not be the physical center-line of the bullet However, this being, with any luck,the REAL world, there are a couple of "catches": Air resistance (drag) and GRAVITY. We will ignore the rotation of the planet in this case. Artillery folks DO NOT ignore it. The bullet is launched along the alignment of the last few inches of the barre and hopefully not "buffeted" too much by muzzle blast as it departs. It will be spinning at the requisite rate but it WILL have a "precession" component, like it or not As soon as the bullet emerges, it is subject ti the aforementioned drag and gravity. The drag starts to slow the bullet. In true Newtonian fashion, gravity acts to accelerate the bullet DOWNWARD at 32 feet per second squared.The net result is that the flight path "trajectory" is a close approximation of a PARABOLA, i.e., a constantly steepening curve. It is the AIR re stance that does the slowing down.At "some point in the trajectory, the bullet will be still pointing on the "line of departure" but it will be tracking the nominal parabola the drag in the shock-cone from the supersonic speed will be doing a bit of a dance with the gyroscopic forces of the spin and the bullet will "realign" (more-or-less), with the trajectory. IF the bullet is not spun fast enough, it will wander off quite a lot; If spun too fast, this takes longer and the "snap-back" is more violent and at greater intervals. As the bullet goes down-range, it's forward "speed" is steadily reduce by the drag. ROTATIONAL speed is fundamentally unaffected. So, in our example, the 16-inch carbines launched the SAME bullet at a couple of hundred FPS slower and with a commensurately reduced SPIN rate. Hence a marginally more "rainbow-like" trajectory, but with "correction" being smaller and occurring at shorter intervals. Thus, the better grouping out to 500yda. the shorter barrel also was effectively "stiffer" than the longer one and thus had less deflection on firing. Apparently there had been some experiments with 1:9 inch twist barrels, but the issue then became failure to stabilize the long tracer bullets. And, given the well-documented "effective use of rifle fire in the battlefield" being almost exclusively inside a 300 yd range, the problem "went away".
On Hornady RUclips there is a person who talks about .22LR or some similar being sent downrange where they have marginal accuracy and then at a certain range, they go 10 feet wide. It was determined they were unstable in flight due to various factors, but after the round dropped below mach 2, the round would suddenly stabilize. At that point, whatever direction it was pointed at, it would stabilize and fly off in that direction. Your story reminds me exactly of this issue. I would be very interested to know if this behavior could be taken advantage of specifically to create wide beaten zones with machine guns to increase their coverage of an area. Whats below doesnt pertain exactly to you ,but to others who have posted here being know it alls about the science of bulletry. Wrong. There is a center of pressure vs center of gravity issue. Its nothing to do with length. Think about archery arrows. They dont fall end over end when fired. They're long and light. Revise your belief structure with science. Go to Hornady youtube and look for internal ballistics, bullet construction, and other similar episodes. They have actual ballistic engineers on their show.
My Bartlein gain twist barrel on one of my 6.5-284 Norma rifles is the easiest and consistently the most accurate rifle I've ever loaded for. Meaning, no matter what I tested, which was a HUGE variety of bullets/powder, nothing shot over 1/2" at 100 yards.....ever (3 shot groups). That INCLUDES working up OCW also
Bartlein and Krieger will sell you one, but even they admit that they can measure no significant improvement with normal rifle calibers. You can check their websites. "Gain twist" was an Italian state secret and used on the 6.5 Carcano rifles, but they decided it wasn't helping and switched away for the subsequent 7.35mm rifles. Apparently gain twist is useful on some military cannon cartridges, though.
All the new PRC caliber rifles have faster than our usual twist rates to accommodate the also new longer and heavier for caliber bullets for longer range competition and hunting. Im sure that standard for caliber bullets will no longer be effective in the PRC cartridges.
Back in the 80’s and 90’s, I had problems losing deer on very close shots but awesome performance past 100 yards. I wonder if this may explain the issue I was having. I switched to a .243 and eliminated the problem. The past few years,, I have switched back to the 270 without the issues I had back in the 80/90s.
Possibly, Terry, but I'd suspect excessive bullet expansion the more likely culprit. Although, with a .277" bullet at 2,900 to 3,100 fps, your whitetails/mule deer should have been venison. Still, weird things happen. I once hit a big whitetail in the chest with a 130-gr. 270 Win. It ran a good 200 yards, leaving but two tiny flecks of blood on the snow. We couldn't follow into the woodlot where it had run until the next morning. We found it frozen in a comfortable pose where it had bedded. The lungs were literally soupy. How it made it that far remains a mystery.
If you stay with mid. weight slugs likely be ok . I think some rifles send the slug yawing at close range , but they stabilize at longer range. This could be why some miss close shots , like charging bears etc.
I have already added a comment, but to clarify one point I really enjoy listening to both of these guys. They are very knowledgeable but to me things have gotten off track a little bit., Everyone talks about BC bullets and shooting 600+ yards, the average hunter doesn’t do that, and that type of shooting hurts a lot of animals , and they suffer terrible death and many are never found by the hunter or should I say, shooter, my definition of hunting and shooting long-distance is two different things !
Here is another concept which may help. While in the bore, the bullet is spinning around its geometric center of form, which, due to imperfections in the bullet, may not be exactly the same as the center of gravity. Upon exiting, the bullet, free of the physical control of the barrel walls, transitions to spinning around its true center of gravity. It is this transition that sets up a slight wobble as the bullet shifts from rotating around one axis to the other. The wobble will diminish as the new axis of spin is firmly established.
re: I have a hard time wrapping my head around going from unstable to stable" That just shows that you have a good grasp on reality. A lot of bullets wobble somewhat after leaving the barrel but straighten out later. Sometimes a change in bullet design can make a difference, especially if it is a big change, like a large flat nose vs round nose, which is probably what happened here. Also modern manufacturing techniques have reduced the "out of balance" problems over what was seen with old bullets. One of the US's top ballisticians (Jeff Siewert) already commented with: "Sorry guys, the wobble happens on virtually all shots; it’s the variation in initial wobble magnitude & direction that causes groups to non-zero in size." Very occasionally, the core slips in the jacket and weird things happen (especially in armor-piercing bullets with tungsten cores). Otherwise, bullets tend to get more stable at distance until they slow down to near the speed of sound (transonic region) where changes in aerodynamic forces sometimes cause wobble, yaw, or other issues. A recent Hornady podcast discussed this when discussing twist rate.
Velocity I believe is more of a matter with overall pressure, bore/bullet friction and the pressure curve.... length of barrel too. A twisting bullet might delay the movement of the bullet, too. So I'm sure it's also a factor... but not as much.
Ron's opening line about bullet stabilization is correct. Full metal jacket bullets tend to tumble after impact and do not follow a straight path through the target. It is related more to the shape of bullet than to the rate of spin. All rotating objects become more stable the faster they are rotated. The only exception to that is if they are rotated fast enough to cause them to lose their shape or come apart due to centrifugal force and heat. Fort Scott ammunition sells bullets based on the design of the bullet cause them to tumble after impact. Any bullet that tumbles after impact is going to have its ability to penetrate changed. The story about bullets going to sleep is an old Goofy, not based in fact, fairy tale.
Berger bullets have a source where you can apply your bullet and twist rate and it will tell you how stable it would be instead of buying boxes of different ammo. Save you hundreds of dollars and headache.
A bullet leaving the barrel is akin to spinning a top. At the beginning of the spin the top makes a big ark or large concentric circles and eventually will stabilize in smaller tighter concentric circles. Same thing happens to your bullet flying through the air.
The spin imparted on a top is from a single point, the tangent of the pulling string. Spin imparted on a bullet is from the lands in the rifling which would be like many strings pulling from different directions with the same force on each string, which reduce the axial arc substantially, plus the surface the top spins on is much more resistant than the air.
However, a bullet has slight imperfections in weight distribution and is spinning at much higher rpm than a top. It spins around center of form while in the bore, but shifts to spin around true center of gravity when free of the bore's physical control. @@williamgaines9784 Same thing with the top, starts out spinning controlled by the string tangent, then shifts to find its own center of gravity when free of the string. Shamoy has it right.
@@williamgaines9784 Not all tops are launched by a string. A small finger spun top on a hard surface will have little friction, dare I say less than the friction of our atmosphere which is capable of reducing bullet speed by half in just a few seconds. All things being equally similar, a bullet launched from a rifled barrel does in fact take a moment to stabilize. Any military sniper will verify that greater consistently is achieved beyond the first hundred meters or so. I took me awhile to understand that until the top analogy was mentioned.
@@shamoy1000 If you think the surface that the top spins on has less friction than the air, then you should be able to strike a match by waving it in air.
Storied professional Don Heath was a professional's professional who used the 9.3x62 for everything, including some combat work. One of his observations was that the 375 H&H did not perform as well as his 9.3, notwithstanding the superior numbers that it generates. Some of this would probably be due to periods when poor bullets were often the only choice, however, this interesting data on twist rate may also suggest some answers.
His analysis generally of the 9.3 in his hands was that it was ideal for some of the softer skinned game, and that one could drill to the "vault" with it on on anything that might require it. The only thing it did not have was the ability to add some knock down on Jumbo. And for that he felt the 500 Jeff was the floor. He did recommend the 375 H&H for the average hunter, but that may have been because of the legal limitations on anything smaller than, and the fact it is a consensus opinion.
Browning improved the very old .270win by introducing a faster twist barrell in the xbolt rifle this year. Hopefully other companies research further into this and catch on as well.
@@reloadnorth7722 Many would. Individuals have been doing this for a long time. The issue is that you might need to use a longer action to fit the long bullets and that factory ammo would be an issue. Factory ammo is generally made to work in the worst case, ie slowest-twist. Some cartridges were designed around particular actions and their limitations, but could be improved for other rifles. For safety reasons, most improved cartridges are given a new name and sometimes changed enough that they can't be accidentally loaded into the old rifles.
You mentioned that this problem occurred with old kynoch style bullets. You did not mention how old the cartridge was. Could this be a problem with old powder going sour? We got a bad powder lot of 4895 in our powder bags in our 105 MM Howitzer that lost range erratically. When we researched it we found that the powder lot was created in 1943! The Army got rid of most of the powder at the end of WW II. However, when new lots come in the Regs say they should be rotated with newer ones but, it doesn't always happen. We drew this lot of powder from Dugway from an underground storage area and that's how it happened.
The 8.6 Blackout is optimized for subsonic speeds. That makes a big difference. Even if you zero at 100 yards, you will get over 30" of drop at 200 yards and over 40" at 225. Misjudging distance just a little can result in a miss.
Bryan Litz: "When my drill turns slow, the drill bit struggles to go into wood." That 8.6 BLK spins fast, maybe 25m to 150m it works well. Now, how do we fast twist that 300WSM concept. Or do we neck the 416RM down so that you can 400grains with twist rate. Just a thought. The drill needs to spin that 400grain weight fast enough between 25m to 200m
What about the 35 Whelen with a 16 twist in the Remington 700? I've read that an all copper 225 or 250 grain bullet wont stabilize under say 4500 ft above sea level.
Copper alloy bullets are less dense than cup and core, so they will be lighter if they are the same shape. A copper bullet will be about 20% lighter than a comparable cup and core but might actually penetrate deeper, depending on design. Barnes has 35 Whelen loads with 180 and 200 grains bullets which correspond to 225 or 250 grain cup and core.
On pointed and round nose bullets, it doesn't take much of an angle to cause a projectile to alter its trajectory. There are documented cases of individuals being shot in the head with both hand hund and rifles where the projectile deflects slightly and follows the skull plate under the skin until it exists the skin on the back side without ever penetrating the skull. I suspect this is what is occurring when the bullets yaw points its axis more tangent to the surface at the moment of impact. This will be exaggerated with both larger diameter bullets, and older bullets that were not as consistent and uniform as what we have available today.
I was watching a video on the 8.6 Blackout on Garand Thumb and they were punching subsonic 338's through 4 feet... not inches, but feet of ballistic gel. 1-3" twist. Why?
The twist of most .30 cal that used accelerators is very similar to the .22 cal barrels that would use the bare bullet, so it is not the rpms as much as the sabot is imperfect and it magnifies any imperfections in the bullet that might have otherwise been corrected by direct contact with the barrel. The .22-250 is not pushing the 55 gr bullet much slower than the accelerator. That other saboted projectiles do better could be that the ratios of core diameter to sabot diameter to overal length is not as great as in the .30 -.22.
It could be that a bullet, especially a longer bullet, flexes slightly when exiting the muzzle, just like an arrow does, and eventually stabilizes further on its trajectory. This could be caused by the rifling itself as it disengages from the bullet. First the frontal portion followed by the base.
Interesting idea, Tim, and not as wild as it first might seem. Bullets do expand slightly while moving down the barrel and they can/do distort somewhat in the barrel, but I've never heard that they flex longitudinally like an arrow. They do emerge with the tip often rotating off their center. This "yaw" usually settles down after 50 to 100 yards.
Why can't we compare slower cartridges like a shotgun. Let's say a sabot slug. Shotgun chokes are there to reduce the spin. Big ball slugs can be delivered through a smooth bore. Sabot slugs on the other hand have a front and tail heavy shape. Newer variations of sabot slugs are using more modern day pistol projectiles. We can also use even slower moving projectiles to determine this. Your typical archery arrow stabilizes the further down range it goes. The spin rate also increases. The most recent theory of archery arrows is F.o.c. (forward of center) balance. I believe bullet construction and shape determine the required twist rate. Longer b.c. bullets make more contact with the lands. The heavier bullets are also using increased pressure to excel them. I believe this is why each platform will perform different with different ammo and load. Some styles of rifling are more forgiving. 5R twist has more land surface area than a 6R. Again compare archery arrows. The short arrow stabilize sooner. And 4 feathers add more twist over a 3 feather construction. The energy with a heavier arrow or a light variations has completely different accuracy. Finally....there is no all around perfect combo. That's why it's called precision shooting. All factors for one specific target.
The old Mausers had faster twist than some modern rifles. I think some pistols may have not enough twist with longer slugs . My old swede only one weight , 120 gr did I see keyhole the target.
Rifles like the Carcanos did this, but it apparently has little positive effect with rifle-caliber bullets. Companies like Bartlein and Krieger will sell you one, but even they admit it does not have a significant affect on accuracy. The vast majority of their competition barrels use normal rifling twist. Gain-twist is apparently very important with some cannon calibers, though.
When a youtuber with decades of reloading experience (not me) claims that cartridges like 6.5 CM or others with 1:8 twist, and using the really long bullets like the Accubond LR are very hard to load for, the question still is unanswered: Why? Not enough jump when seating the bullet? Too fast? Too high of twist rate? Maybe long range (1,000 yds) loaded cartridges don’t work optimally at close range with longer bullets? Maybe some slo-mo footage could shed some light on what’s really going on. Enquirin’ minds wanna know.
The required twist rate is determined by the LENGTH of the bullet, NOT THE WEIGHT. Longer bullets REQUIRE higher twist rates. We only see over-stabilization when the twist rate exceeds what is required by the length. Like it or not, needle-like bullets at higher twist rates are the future. The reason we have not had them before now has nothing to do with accuracy. If that were the case, the faster twist-rate rifles would be less accurate, and we do not see any indication of that. We have not had higher twist rates due to bullet construction and cost. Higher twist rates wear out buttons faster, and lead can only hold up to a specific RPM, depending on the thickness of the copper jacket. However, with the advancement of solid copper bullets, we can now move beyond what would typically blow a lead bullet apart in flight.
Wrong. There is a center of pressure vs center of gravity issue. Its nothing to do with length. Think about archery arrows. They dont fall end over end when fired. They're long and light. Revise your belief structure with science. Go to Hornady youtube and look for internal ballistics, bullet construction, and other similar episodes. They have actual ballistic engineers on their show.
@@neglectfulsausage7689 Arrows have fletching at the rear to create drag for stabilization. Pellets do the same thing with their skirts. As a result, they don't require spin to stabilize. You have to fully understand all the science to realize I am correct. Any ballistic engineer will agree with me. God bless. P.S. One of Ron's next episodes had a guest who confirmed what I said here, but not directly. I will see if I can find it.
@@neglectfulsausage7689 John McAdams was mistaken, but this guy was spot on. ruclips.net/video/qjeyH_0X6Wg/видео.html All guests can't be a home run. Ron may have even realized John was incorrect then but didn't want to point it out.
Instead of a 375 H&H, use a “rifled barrel 12 gauge shotgun” with a 1-4, 1-6, 1-8, or 1-10(yes Vortex makes one) scope using “brennekeusa” Brenneke SLUGS for hunting African Water Buffalo or Grizzly protection.
This sounds more of a terminal affect ie peneration n expansion based on RPM or Twist Rater.. Wonder if anybody has done gel test with different bullets n weight calibers etc n twist rates.
It does seem to me that if the twist rate were absurdly high, it would lead to higher pressures as the bullet would have more resistance from the lands in the barrel. That higher pressure surely could affect accuracy.
The twist wasn't absurdly high in the example, but pressure is controlled/limited by SAAMI specs per cartridge stated as MAP, maximum average chamber pressure. This can vary shot to shot and there's a large, built in fudge factor, but changing twist from 1-12 to 1-10 or even 1-8 isn't likely to radically increase pressure. And high pressure doesn't necessarily ruin accuracy. Many cartridges are rated 65,000 psi and just as potentially as accurate as those rated 50,000 psi.
So the 375 that didn’t penetrate the buffalo skull at short range was solved by going with a longer, heavier bullet? To conclude that the root of the problem was too much gyroscopic stability makes no sense to me… By switching to a longer, heavier bullet… the dominant change is an obvious increase in sectional density… which increases penetration potential. IMO the solution to an inadequate penetration problem at short range is: 1) use bullets that retain most or all mass but have reliable controlled expansion. 2) choose longer, heavier bullets with a high sectional density… high sectional density yields greater penetration.
Trevor, surely you are right about the longer, heavier bullet increasing penetration potential, but I'd argue as a solid (FMJ or monometal) rather than controlled expansion, although some of our best CE bullets can and do penetrate ridiculously well. Such was the little 270-gr. Shock Hammer I used to brain a buffalo with Zambezi Delta Safaris last year. Despite its nose petal shedding design, that Hammer drove through the brain and into the heavy, thick Atlas bone at the back of the skull, which it cracked, but failed to punch through. Hardly mattered because that bull was dead on arrival. As for that gyroscopic stability issue, I think Robertson was arguing that the initial yaw of the bullet nose contributed or led directly to the off-course penetration. Because bullets, regardless the twist rate, emerge from muzzles with variable yaw, they can strike close targets with the nose/tip quite a bit off axis. This means the impact/friction of hide/muscle/bone on one "side" of the nose directs the entire bullet off its flight path. Rather like striking a branch. Hunting lore is replete with bullets ending up in strange places far from their initial line of flight. But I agree with you that "too much gyro stability" was not the issue. Less gyro stability would likely only increase the yaw, I would guess. But I could be wrong. At any rate, a longer, heavier bullet would/should increase penetration and any degree of yaw. Thanks for offering your studied opinion.
@@RonSpomerOutdoors Wow Ron! Thank you for the comprehensive reply!… The specific bullet type that I had in mind when I suggested a long and heavy weight retaining controlled expansion bullet for achieving adequate penetration on beastly bone was the barnes TSX… these are the non tipped copper monos with the hollow point. But… truth be told I am definitely the student here as I have zero experience hunting giant African game like cape buffalo or elephant! Regarding the issue of too much gyroscopic stability… It is my understanding from listening to ballistics gurus like Jayden Quinlan and Bryan Litz… that cheap conventional lead tip cup and core bullets can suffer from degraded accuracy at high rates of twist. The issue is that flaws in the radial inertial concentricity due to uneven jacket thickness or lead density or uneven tip shape cause exacerbation of the yaw of repose when the bullet hits the air resistance and goes through its wobble cycles at higher rates of spin… so… higher spin can cause more yaw in cheap bullets with poor cross sectional or radial balance. Eeek… I hope that’s not too much word salad. Cheers!
This would be Caused by bullet jump the bullet is Microscopically hitting the lands and grooves at a odd angle. manufacturer's specifications are on average smaller than most gun chambers, on Purpose for magazines feeding. I bet if one was to hand load that 375 to the tightest of tolerances that Initial Wobble would be minimized
What is differance between 20inch barrel 1.8 twist and 26inch barrel 1.10 twist in same calibre ? 2.5 twists in 20 inch per barrel lenght anf 2.6 twist in 26 inch barrel..?
It doesn't matter. The rate of twist is consistent regardless barrel length. Rifling that twists at a rate of 1 turn in 8 inches spins a bullet the same in an 8" barrel, 18" barrel, 4" barrel, 40" barrel. In a 26" barrel with 1:10 twist rate the bullet would complete 2.6 complete turns (not twists) while still in the barrel. With 1:8 it would complete 3.25 complete turns. Big deal. The bullet's rate of turning or spinning around its axis matters when it's free of the barrel and in the air. Its gyroscopic motion (spinning) stabilizes it more or less nose forward so that it does not tumble.
Hi Ron, that is what i dont understand...i meant 1.8 twist in 20 inch barrel the bullet makes 2.5 rotations...so it is less than a 1.10 twist in 26 inch barrel that a bullet makes 2.6 rotations before leaving the barrel...if increase lenght of 1.10 twist barrel rotation of bullet can also go up to 3.25 rotations like a 1.8 twist 20 inch barrel.. thanks
For artillery that is shooting at high elevation that is correct. For most rifles at distances less than a couple miles, not so much. In Bryan Litz's books about long-range marksmanship with rifles, doppler radar showed that faster twist tends to help at longer distances. The faster spin helps the bullet "go to sleep" quicker (as Ron said), so it has less wind resistance and stays faster. Also, as the bullet slows into the transonic range, faster spin keeps it point-forward. Many bullets lose stability as they approach the speed of sound and yaw wildly.
It’s interesting information but to me it really doesn’t make a difference when it comes to generalized hunting with the cartridges that we are most familiar with, I also found it interesting that Ron months ago talked about someone hunting in Africa years ago with a 7 mm Mauser killing so many elephants with one shot, and now it seems in conversation That more weapon is actually needed and why,
Some of this is due to bullet construction and velocity. If you fire a bowler ballistic tip at 3000 FPS out of a 7mm rem mag and shoot a bull elk at 15 feet you will get wayyyyyyyyyyy less penetration than you would at 400 yards. This has NOTHING to do with twist it is simply velocity being too high for that bullets construction on the very dense target that elk are. But if it is a case where you are shooting solids then yes it probably a stability issue. If the projectile doesn’t hit square to the trajectory path then it may rumble or curve in the target providing less penetration than at a slightly greater distance where the bullet is more concentric in flight. So yes there is a nice ideal twist rate for a given load. But this is probably way oversold especially for North American big game hunters. This is 99% a dangerous game issue. In that case definitely worth considering.
I wonder how similar this is to the behavior of bullets in water, in the sense that larger bullets slow down faster vs. smaller bullets. I am thinking in terms of something like a fluid dynamics problem, or how space craft will bounce off the atmosphere if they hit at the wrong angle or a bullet will skip off water surface due to the water surface tension. That extra energy, is going somewhere as the bullet leaves the barrel, hits the air, and is pulling on the bullet in the wrong direction, creating drag like a wirlpool suction effect, to slow the bullet down, until it stabilizes. That is probably overly simplistic. Just a thought.
Physics state that the faster you rotate any object including a out of balance tire the more stable it becomes. You have to obey the speed limit when you're driving a car. If you kept rotating a tire fast enough the rotational velocity can exceed the acceleration outward due to a imbalance moment of inertia. When that happens a out of balance tire will become more stable but when it's on a car it has to obey speed limit or you get a ticket from the cops and cars can only spin wheels as fast as the car can go.
I have wondered if high twist rate accuracy issues with lower weight bullets might have something to do with bullet quality. Bullets are typically considered homogeneous. But what if the center of mass is slightly off of the center axis of the bullet? Maybe from a small nick on the bullet casing. Would this slight rotating imbalance become increasingly noticeable at higher spin rates, similar to an automobile tire spinning faster on an axel? I don’t believe there are perfect bullets, but some are likely better than others. Increases in rotational speed above what is required for stability might worsen rotational imbalance issues. I have no factual data or reference to support my suspicions.
@@bobbob8229 yes and his wife, so a woman can drop elephant with a 270 but a man wimpy uses a belted magnums. Read up on some of those old timers that could kill big game with shot placement instead of putting a bunch of holes in and around the arse of an animal. If you watch Bill moles the Alaskan guide he had a German man drop a 10 foot plus brown bear with a 270 and he has had clients with 375h and h and empty their gun twice because they thought they were a man. Nope
@@bobbob8229 there is a man here in Blanco tx back in his glory days killed some of biggest elk in Colorado with a 222 Remington, mid 90s now. Just did it to prove it could be done. Shot placement is the game. If you want to talk about numbers Wilfred wastal out law hunter, probably 60ty bucks a year off the king ranch. Model 99 savage 243 80ty grain bullet, my brother inlaw Harlow kibbe Model 70ty Winchester 243 80ty grain bullet I've seen him drop deer pushing and past 500 yards. Neck shot every time, I've killed many deer on the king ranch 16 inch savage 340 in 222, when you have to run it's light, and believe me when you hear the hammer of a colt cock you are not going to say good morning! You put trees mesquite and motts of mesquite between that colt and your ass,it's happened and have witnesses.
Ron and/or John, can you comment on the new 8.6 Blackout and twist rate? There’s a video out showing the 8.6 with a really fast twist-maybe 1 turn in 3"- and they were claiming it makes a big difference on the terminal performance. Specifically, it makes a a much larger permanent wound cavity. Thoughts?
It helps monolithic bullets open up faster and wider but can cause fragmentation and core-slip issues with cup and core. The effect seems much more important for subsonic ammo that is traveling too slow to cause wounds from the temporary cavity.
I don't think so. Bore rider bullets engage rifling with a small , raised ring along the bore diameter shank. Two of these, fore and aft, might increase accuracy, but one is enough to impart spin.
I’ll put in my two cents worth, but the problem is more leaning somewhere else than where everyone is pointing; I would seriously look at the crown of the muzzle. If you’re having these issues if you get gas escaping from one side of the base more than the other as the bullet exits, you’re going to tilt the base of the bullet generating a wobble, The severity of the wobble determines the distance beyond the bore at which point the bullet will re-stabilize, directly impacting group size. This effect is more pronounced with spire point bullets Because of the change in weight decreasing toward the point. Most of my hunting is with pistols, a lot of it in the old days with the round nose Before realizing they are not very effective for hunting animals due to greatly reduced tissue damage as that round nose squeezes its way through tissue, without making much of a wound channel until the bullet starts to tumble, which, after many many deer and hogs, a round those bullet is almost guaranteed to tumble, which, depending on the thickness of the animal could be a good thing, because of a larger, wound channel occurring at that point, but on narrower animals The tumble may occur as it exits the far side, creating very little damage to organs prior to a long, tracking job. I learned long ago that flat nose bullets tend to penetrate media and a very much straighter nose, first attitude and straight line penetration; while violently slapping tissue outwards creating a much larger, permanent wound cavity. We can “one-up” this by milling a slight concave flat meplat, get even better penetration, the dynamics of which I am not quite understanding yet. In all of this, I’m talking about 44 and 45 caliber magnum handguns using hardcast lead Flat-nose bullets On feral hogs. I’m going to fully assume any non-expanding bullet of the same nose design would offer the same advantages in rifle calibers, as big as you want to go. Watching slow-mo footage Of bullets exiting barrels, it appears to me that the more equal weight from the trailing edge to the meplat Inherits less wobble at the bore departure than can occur with longer more tapered bullets. Meaning a wadcutter style bullet more possibly have less wobble than anything short of that I don’t know what they make for African solids because I don’t see me making a trip to Africa. Maybe some of y’all know if they make bullets (solids) of this nature. Just to quickly add the bullets that I am old are so hard they do not expand, but it’s difficult to tell the difference between that, and a hollowpoint, as far as damage is concerned, and deflection is much less with the solids at least on the Even really big hogs. I have to admit it took me a half a century of Bullet, casting, and hand loading to learn this.
In my humble opinion it is much more about deflection at higher speeds. I had better penetration with reduced bullet speed in moose at close range with the same projectiles. The old rounds with speeds between 2200 and 2400 ft/sec penetrated like a charm, mostly in a straight line. Make them faster and every little tissue difference in the animal deflects the projectile from its original path! Initial shock is higher when you get closer to 3000 ft/sec, which is evident in the drastic dropping of many thin skinned species. Gel tests are in this respect misleading, since they do not offer the tissue variability found in animal muscle tissue including sinews and fatty areas. Twist rate is important regarding bullet length but has little to do with the discussed penetration problems. It all comes down to bullet speed.
@piercer2 Seriously, though, overstabilization is not really an issue. A higher spin rate should help with stabilization, if anything. The main issue is that it is possible to spin thin-jacketed bullets so fast that they come apart in the air, but I have never heard of it happening with a setup like yours. You might even be able to find out the max allowable spin rate for your particular bullet from its maker.
I doubt it. 5R just reduces bullet engraving/squeezing because the lands are more sloped into the grooves and opposite a grove rather than opposite another land. So, reduces bullet deformation potentially increases accuracy. Less barrel fouling is also claimed.
Not only is the bullet affected by the twist rate, but it affects the barrel vibration too. Keep that in mind when thinking about the accuracy, and bullet yaw too...
It's all about balance ! Velocity and twist rate are linked. The faster a bullet spin the greater the wound channel: very useful for taking long shots when bullets drop below 1800fps it helps a great deal as expansion or fragmentation is minimal but too much spin is not that useful at close to "normal" hunting range as it can be very destructive on game. That's why you usually found the 7-08 with 9 to 9.1/4 twist rate and 7 RM with 9.5 to 10 twist, the later being a much faster cartridge !
So if these old style bullets had that problem in the 375,surely it would have reared its head more than twice in the more than 100 years of shooting large dangerous game in Africa with the 375 h h?! Huh?
It was an honor and a pleasure to be on your show Ron! Thanks again for the opportunity!
What about early Weatherby Mark V rifles in .300 Wby Mag? They evidently only had 1:12 inch twist rates. How did they handle the 200 and 220-grain bullets?
@@DJones476 good question. Every bullet needs to rotate at a certain spin rate for stability. This spin rate is a function of the rifling twist rate (faster twist rates equal a faster spin rate) and bullet velocity (faster velocity equals faster spin rate). You can calculate the spin rate of a bullet by multiplying the muzzle velocity times 720 and then dividing that number by the barrel twist rate. For instance, a bullet fired at 3,200fps from a rifle with a 1:12 twist rate is spinning at 192,000 RPM. A bullet fired at 2,666fps from a rifle with a faster 1:10 twist rate has the exact spin rate. With that in mind, a very high velocity loading like the 300 Weatherby can get by with a slower rifling twist rate. Plus, I'll bet those older 200gr and 220gr 300 Weatherby loadings that worked with a 1:12 twist rate were pretty basic round or pointed bullets that weren't especially long or sleek compared to the really high BC stuff we have today like the ELD-X or AccuBond Long Range, and therefore didn't need as fast of a spin rate for stability. Make sense?
@@Thebiggamehuntingblog Yes. Thank you.
@@Thebiggamehuntingblog 192,000 RPM, Wow, that's almost as fast as my 318 Detroit was turning coming down the Grapevine in fourth gear after I lost my brakes!
And any dude that don't find bullets and twist rates worth a look probably also puts water in his whiskey.
John I like your strategically placed 2ID/4ID display box. You earned, it so here you go. Thank you for your Servings.
The topic that needs to be discussed with a big channel like you is how slow twist rate guns can shoot long high b.c. bullets. For example my 1in10 twist 270 Win shoots the 165 ABLR incredibly accurate. I have tested it out to 800 yards. The 270 Win will also shoot the 170 gr EOL extremely well. I also have a couple of friends with 270 WSM rifles that shoot the 165 ABLR at much lower elevation than me with great success.
Wrong. There is a center of pressure vs center of gravity issue. Its nothing to do with length. Think about archery arrows. They dont fall end over end when fired. They're long and light. Revise your belief structure with science. Go to Hornady youtube and look for internal ballistics, bullet construction, and other similar episodes. They have actual ballistic engineers on their show.
@neglectfulsausage7689 I have video proof on my channel of shooting high b.c. bullets in slower twist rate guns. Just recently I showed a 1in9.5 7mm-08 getting sub Half MOA with the 180 gr ELD-M.
Speaking of Hornady... did you know they themselves admit you don't need the faster twist rate in their reloading book?
Ballistics is such an interesting science. Bullet shape for and aft, density, pressure, combustion rates, twist rates, muzzle crown. I worry for anyone who wouldn't find it interesting.
Most cartridge designs have been around for decades; the loads are tried and true (and safe). Here's a novel idea! Instead of trying to fit a square peg in a round hole, why not establish a goal for speed or accuracy and find a standard barrel, cartridge, bullet and load that do so without unacceptable risk? For some reason sites like this one seem to be a magnet for guys who want to be the first to break a record. I'm glad that Mr Spomer preaches a safe and sane approach.
Awesome 2 legends together on a podcast awesome thanks so much for Great information
Glad you enjoyed it!
I think that the "old Kynoch bullets" and "round nose" are the pertinent points. The Guest also mentioned that the PH switched from old-style round nosed bullet to flat nosed. This is very important. A large flat nose ( 65+% diameter is often mentioned) tends to travel through tissue in a straight line. Round nose designs and those with very small flat noses are much more likely to yaw.
If you look at high-speed photos, almost many bullets yaw significantly immediately after leaving the muzzle. It often takes well over 100 yards for a bullet to "go to sleep". The flat-based bullets favored by short-range benchrest shooters yaw less, but have lower BC, which is why they are only used for relatively short ranges. FWIW, in WWI, the British noted that their 303 bullets penetrated sandbags best at about 200 yards. This implies significant yaw up till that point.
It is of note that "fleet yaw" in military 5.56x45 ammo was noted as an issue for its lethality. For the FMJ bullets that depend on yawing for damaging tissue, a very small yaw of several degrees turned out to be very important. Bullets that hit the target perfectly end-on tended to punch straight through and cause little damage. A lot of work has been done to ensure that modern military bullets will yaw rapidly.
That is the reason why. In África they began yesting the Meplat point.
Beca use, Round nos hitting heavy bone tend to to deform and Tumble...
John said it... "very old"
Lapua has some helpful content on their website on the matter. The issue with an over stabilized bullet is that it is flying nose up and not in line with the trajectory.
I think this explains nicely the anecdotal penetration issue as the bullet impacts with a cross section rather than the pointy end
"Key holing" is how I heard it. Never thought of it happening fresh out of the muzzle.
I think you've explained it nicely, Nikos. But I would add it could also be nose down at impact because the spiraling nose has yaw (left to right) and pitch (up and down) around the bullet axis. Who can predict at what specific tilt the nose is upon landing? This is why flat nosed bullets are famous for straight line penetration. Less likely to present a degree of cross section/flank for deflection.
@@RonSpomerOutdoors the wobbling would be dynamic stability, or the lack thereof 😁. From what I read this should only be really relevant past 600 yards. Do you think it is a factor on very short distances as well?
Sorry guys, the wobble happens on virtually all shots; it’s the variation in initial wobble magnitude & direction that causes groups to non-zero in size. The wobble DOESN’T mean the bullet is “unstable” unless the wobble grows with range, then it’s said to be “dynamically unstable “.
Mr Siewert is a ballistics expert and knows more than any of us. Many bullets wobble a bit at launch and few have "gone to sleep" at the short distances mentioned in this video. I suspect that the important thing is that the longer, flat-nosed bullets that the PH switched to just tend to travel in a straighter line through tissue than the old round nosed ones.
Greatest collaboration video! Sounds like factory ammunition is more dependable than handloading
In testing for the 8.6 blackout, they did test 1:1 twist rates. They only reason they settled on 1:3 was because of barrel life, not terminal performance. They found 1:1 to be better.
Source please? The 8.6 Blackout is an unusual case since they are traveling slowly (subsonic) and depend on wide expansion to kill game. The fast twist seems to help some bullets, especially monolithic (copper) ones to expand widely and damage more tissue if it hits at relatively low velocity. Broadhead arrows use this principle as well. Such fast spin will cause normal cup and core bullets to fly apart at typical rifle speeds of over 2000 fps.
From the mouth of the creator of the blackout. He said that bullet manufactures would have trouble stopping bullets from flying apart the moment they exit the barrel. Barrel life wasn't the issue. He was recently on Demo Ranch and said this. 1:3 was the sweet spot where off the shelf bullets wouldn't fly apart.
@@shperax That makes sense. I know that just increasing the twist from 1:7" to 1:5" in the 300 Blackout caused some bullets to expand as soon as they left the barrel.... and that was for bullets designed specifically for the cartridge.
I have read but not confirmed that when 8.6 BLK was being considered for SAAMI approval, Hornady objected to 1:3 twist and wanted 1:5. My guess is that has to do with bullet design/manufacture.
Thinking about this, the bullet spin and the expanding gases pushing on bullet as it leaves the rifled barrels need to be tuned to prevent spin yawing. Having a precise or geometric balance barrel crown would also help by allowing the bullet complete circumference area lose contact with barrel instantaneously and the expanding gases exiting the barrel uniformly flow around the bullet as it leaves the barrel.
Interesting video. Thank you.
A common problem with the old Kynoch style solids is fish tailing which can cause a tumbling. Especially at close range and high velocity. Modern monolithic and modern flat point very sturdy bullets like Hornaday DGS don't do this. Riveting is also a problem in those old ones. The PMP 286gr. Brass solids were developed specifically for this issue for elephant culling in the Kruger park
Was the cartridge hand loaded? Was the bullet defective? Was it seated off-center in the neck? Was it off-center in the throat? How much free-bore did the barrel have? What was the throat diameter ratio?
I have had only one gun that seemed to have too high a twist rate, which was a puzzle at the time. I have a Dan Wesson 44 mag with an 8 inch barrel with a compensator with some copper plated bullets which was very accurate out to 25 Yds, but afterwards the bullets seemed to go wild. I also noted that when I did hit the target the bullet hole had a tail on it. The jacket seemed to be spinning off the bullet and making it unstable. Sometimes also keyholing. Luckily the Dan Wesson is designed to easily change barrels, and changing the barrel seemed to solve the problem. I suspect that the 8 inch barrel was meant for some specialty bullets. That side ported barrel also had huge muzzle blast, the shooters near me usually moved. Although as far as needing a powerful rifle to kil elephants. I beleive kiliminjaro bell took several hundred elephants with 7x57 but was an expert on bullet placement.
what about the ricochet effect because of angle of impact,bone density etc?
Hi Ron, love your show and testing my knowledge often and coming away with a new perspective that generally makes me feel I am better informed after your show than before. Why is twist rate so susceptible to different schools of thought? I used to believe it was about the mass of the projectile that required a faster twist rate to stabilize a heavier bullet. Listening to you for some time now and some additional research reveals that it’s the length of the projectile. Now your guest expert explains that it’s the weight that matters. Color me officially confused. Surely there must be empirical data to support one or the other. What should we believe?
Thank you for keeping my knowledge ego in-check.
Best,
John B
Winchester, I suspect much of the confusion results from decades of everyone believing and repeating that heavier bullet required faster twist to stabilize. This was true once but only because heavier bullets were LONGER by necessity. Most ammo makers set things up with rifling twist adequate to stabilize the heaviest (longest) bullets they wanted their cartridges to shoot. Thus, the U.S. Military set up the 30-06 with 10" twist to stabilize their 220-gr. round nose. A 220-gr. Barnes TTSX (if there even is such a thing) would not stabilize even though the weight is the same because the length is not! There may be some subtle weight contributions I'm not aware of but John was that might be at play, but all my research shows length, length, and length.
@@RonSpomerOutdoors thank you for clarifying once again.
Well done
Enjoyed the discussion. It sounds like a damaged bullet because of the inconsistencies of the events.
This makes sense I shoot a 8x57 and it likes the heavy bullets because it was developed for 196 grain bullets 180s shoot nice groups while 150s open the groups out and old 120 more so.
This is probably due to the wear in the barrel throat. Lighter bullets have a shorter shank and are more likely to be slightly sideways as they travel through the barrel. An old trick for used barrels was to choose a bullet with the longest full-diameter shank. This was often a heavy bullet. One of the features of a "match chamber", or modern chambers like the PRC and Creedmoor series, is to provide a long section of very tight freebore to ensure that the bullet is properly aligned as it enters the rifling. These days, the clearance is often half a thousandth of an inch in that freebore section to give an idea of what is now common.
I've been loading for 40 years for hunting and competition. I've shot out the barrel in a .300 Weatherby,, it was used for a lot of long range shooting. Barrels are like tires on your car in a sense. It all depends on how you use it. I often hunt with a 54 year old 7mm Magnum, and a 60 year old .300 H&H, as well as a 70 year old .375 H&H. You take care of then, and don't abuse them, they'll out last you. After loading thousands of rounds over the years, I can honestly say I've had zero issues as far as the belt. Belted or beltless, makes no difference to me.
Yea theres a lot of factors in this weight shape powder and twist rate of ammo its why u test to see what ammo works best for ur guns and me in my 30-06 i oil my barrel before going out to get a smooth straight long range shots.
I bought a tikka t3x in .243. I wanted to shoot deer/pronghorn with 100gr norma, Hornaday soft point ammo. At 100yds, I was moa but at 300 yds, I was almost off paper - even 90gr eld-x. The tikka comes with 1 in 10 twist (the original 1955 twist rate). After a lot frustration and ammo, I put a new pac nor barrel on the gun with a 1 in 8 twist and the problems went away. Could it be that manufacturers need to rethink twist rate with all the new bullet designs?
I watched some football games where the quarter back made a long pass, the ball had similar behavior mentioned by you guys, where maybe within 10 feet when the ball left the thrower’s hand it looked not stabilized and flew a bit wonky, but as it travelled further it became more stable and caught by the guy in the front. Kinda make sense as mentioned in the video where the 375hh may over stabilize in a short distance and do not perform as expected, but it reaches it’s best performance in a mid to longer distance.
Excellent analogy, Justenzo.
Yes
Does that mean it has to do with were the twist is being applied? So if the area that engages the rifling is not center of mass it would pitch and yaw initially but settled into stability
I think you're onto it, awsomedude. The center of gravity in the bullet and its relationship to the center of pressure are at play. @@awsomedude12345678
@justenzo928 I just watched over a 100 of NFL longest passes in slow motion. My eyeballs say you are full of adam schitt. Every football throw that started out wobbling stayed just as wobbling until they were caught. Some started fairly stabile became more wobbly after reaching the peak of the parabolic arc and became less stabile on the latter half of their flight. What you said is complete B.S. The ignorant, story that bullets and footballs go to sleep, is a B.S. made up fairy tale. In physics there is some thing called summation of forces. The net force is what has meaning. "May the the force be with you" is another Hollywood fake fairly tale. The NET force is the summation of forces and the one that has meaning. People who say a top that starts out wobbling goes to sleep and starts spinning true, are not properly summing the forces when comparing that to bullet or football. If you drop a wobbling spinning top off the Empire state building it will stay wobbling until it is acted upon another force that causes it to resist wobbling. Like letting one end of the top come in contact with the ground which is not moving in relation to spinning top. The force of the ground acting on one end of the top is what forces it to stop wobbling,,,,,,, NOT because it goes to sleep or some other ignorant theory!
I like your first question Ron ,,,,, so this is a twist rate problem ,,, if happened as described could have been a number of things caused it ,,,, referring to the bullet on the elephant tongue
You also have to remember that a faster twist rate equates to higher chamber pressure and also slower velocities.
The pressure drops quickly after the bullet leaves the case. The velocity won't be affected much because it is countered by the round remaining in the barrel a fraction longer and gets pushed more because it is pressure over time.
Effect of barrel rifling twist on peak pressure is negligible in my experience.
@@jeffsiewert1258 both this comment and the guy in the interview don’t quite have all the physics worked out.
You're thinking about it correctly, but you also have to take into account what that increase in pressure does to the burn rate. It's impossible to determine through mere speculation. However, it is safe to say, based on simple physics, that it requires more energy to push a bullet to a given speed with a faster twist than it takes to push the same bullet to the same speed with a slower twist. What this looks like in a side by side comparison real life experiment might be strange though, since the different factors could change the rate at which the powder delivers its energy.
The difference in energy required w/fast twist vs slow twist rifling is on the order of 0.05% of the total energy available. You’d get more swing in peak pressure from barrel-barrel differences in bore dimensions.
Is there a chance that there is a variance in projectile velocity large enough to cause this stability issue?? Idk, but that makes sense. But, also, there surely would be a noticeable difference in recoil that would be a tip-off to that being the reason.
These issues of destabilization can be caused by damage to the mouth of the firearm. A chipped muzzle can cause pressure to exit earlier on one side and push the bullet out of balance. This could perhaps, as you say, correct itself in flight after a certain number of yards. That is one issue that I do not hear mentioned in your conversation. The old .505 Giggs's spitting hole may have been damage in its long travels.
I watched a Reloading video about the .22 Creedmoor where long heavy bullets were properly stabilized with fast twist rates, but lighter shorter bullets were going into the target sideways and breaking apart with those same twist rates. We all know that the .22 Creed makes some very high velocities with lighter bullets. I came away from that with a better understanding about too fast twist rates with lighter bullets for caliber and cartridge.
BINGO! on bullet "length" being critical for a given twist rate.
I first picked up on the "stability" issue shooting military matches using the Steyr AUG in 5.56 NATO, which uses a 62grain, composite cored bullet. (SS-109 / M855 / F1, etc.) The STANDARD twist for those rifles is a very fast 1:7" twist. This is NOT necessarily needed to stabilize the "ball" projectile, but to tame the ludicrously long L-110 / M856 TRACER bullet.
The "SAW / LMG" companion, the FN Minimi / M249, had the same twist, stamped right there on the barrel, specifically to stabilize the tracer ammo.
So, what was the "tell" on "over-stabilization"?
Longer ranges. We were noticing weird group "blowout" at 500 yards. This from rifles that would put ten rounds into a palm-sized group at 300.
The exception was that troops with the 16" CARBINE barrels were sweeping the pool at 500.
Enter the concept of "over-stabilization".
A the bullet leaves the muzzle, it is (hopefully) spinning. However, there is no such thing as a "perfect" barrel (or crown" and certainly no "perfect bullets.
As noted in this video, bullets are KNOWN to "spiral" around the trajectory. The "boffin" term is "precession". The bullet will, eventually start to rotate around its OWN centre of mass, which may not be the physical center-line of the bullet
However, this being, with any luck,the REAL world, there are a couple of "catches": Air resistance (drag) and GRAVITY. We will ignore the rotation of the planet in this case. Artillery folks DO NOT ignore it.
The bullet is launched along the alignment of the last few inches of the barre and hopefully not "buffeted" too much by muzzle blast as it departs. It will be spinning at the requisite rate but it WILL have a "precession" component, like it or not
As soon as the bullet emerges, it is subject ti the aforementioned drag and gravity. The drag starts to slow the bullet. In true Newtonian fashion, gravity acts to accelerate the bullet DOWNWARD at 32 feet per second squared.The net result is that the flight path "trajectory" is a close approximation of a PARABOLA, i.e., a constantly steepening curve. It is the AIR re stance that does the slowing down.At "some point in the trajectory, the bullet will be still pointing on the "line of departure" but it will be tracking the nominal parabola the drag in the shock-cone from the supersonic speed will be doing a bit of a dance with the gyroscopic forces of the spin and the bullet will "realign" (more-or-less), with the trajectory. IF the bullet is not spun fast enough, it will wander off quite a lot; If spun too fast, this takes longer and the "snap-back" is more violent and at greater intervals.
As the bullet goes down-range, it's forward "speed" is steadily reduce by the drag. ROTATIONAL speed is fundamentally unaffected.
So, in our example, the 16-inch carbines launched the SAME bullet at a couple of hundred FPS slower and with a commensurately reduced SPIN rate. Hence a marginally more "rainbow-like" trajectory, but with "correction" being smaller and occurring at shorter intervals. Thus, the better grouping out to 500yda. the shorter barrel also was effectively "stiffer" than the longer one and thus had less deflection on firing.
Apparently there had been some experiments with 1:9 inch twist barrels, but the issue then became failure to stabilize the long tracer bullets. And, given the well-documented "effective use of rifle fire in the battlefield" being almost exclusively inside a 300 yd range, the problem "went away".
On Hornady RUclips there is a person who talks about .22LR or some similar being sent downrange where they have marginal accuracy and then at a certain range, they go 10 feet wide. It was determined they were unstable in flight due to various factors, but after the round dropped below mach 2, the round would suddenly stabilize. At that point, whatever direction it was pointed at, it would stabilize and fly off in that direction. Your story reminds me exactly of this issue.
I would be very interested to know if this behavior could be taken advantage of specifically to create wide beaten zones with machine guns to increase their coverage of an area. Whats below doesnt pertain exactly to you ,but to others who have posted here being know it alls about the science of bulletry.
Wrong. There is a center of pressure vs center of gravity issue. Its nothing to do with length. Think about archery arrows. They dont fall end over end when fired. They're long and light. Revise your belief structure with science. Go to Hornady youtube and look for internal ballistics, bullet construction, and other similar episodes. They have actual ballistic engineers on their show.
Would love some info on gain twist rifling, I have heard varying things about it, mostly good.
My Bartlein gain twist barrel on one of my 6.5-284 Norma rifles is the easiest and consistently the most accurate rifle I've ever loaded for. Meaning, no matter what I tested, which was a HUGE variety of bullets/powder, nothing shot over 1/2" at 100 yards.....ever (3 shot groups). That INCLUDES working up OCW also
@@Accuracy1st I will delve into it further.
Bartlein and Krieger will sell you one, but even they admit that they can measure no significant improvement with normal rifle calibers. You can check their websites. "Gain twist" was an Italian state secret and used on the 6.5 Carcano rifles, but they decided it wasn't helping and switched away for the subsequent 7.35mm rifles. Apparently gain twist is useful on some military cannon cartridges, though.
All the new PRC caliber rifles have faster than our usual twist rates to accommodate the also new longer and heavier for caliber bullets for longer range competition and hunting. Im sure that standard for caliber bullets will no longer be effective in the PRC cartridges.
Back in the 80’s and 90’s, I had problems losing deer on very close shots but awesome performance past 100 yards. I wonder if this may explain the issue I was having. I switched to a .243 and eliminated the problem. The past few years,, I have switched back to the 270 without the issues I had back in the 80/90s.
Possibly, Terry, but I'd suspect excessive bullet expansion the more likely culprit. Although, with a .277" bullet at 2,900 to 3,100 fps, your whitetails/mule deer should have been venison. Still, weird things happen. I once hit a big whitetail in the chest with a 130-gr. 270 Win. It ran a good 200 yards, leaving but two tiny flecks of blood on the snow. We couldn't follow into the woodlot where it had run until the next morning. We found it frozen in a comfortable pose where it had bedded. The lungs were literally soupy. How it made it that far remains a mystery.
If you stay with mid. weight slugs likely be ok . I think some rifles send the slug yawing at close range , but they stabilize at longer range. This could be why some miss close shots , like charging bears etc.
I have already added a comment, but to clarify one point I really enjoy listening to both of these guys. They are very knowledgeable but to me things have gotten off track a little bit., Everyone talks about BC bullets and shooting 600+ yards, the average hunter doesn’t do that, and that type of shooting hurts a lot of animals , and they suffer terrible death and many are never found by the hunter or should I say, shooter, my definition of hunting and shooting long-distance is two different things !
I have a hard time wrapping my head around going from unstable to stable. I believe something else in play here.
Here is another concept which may help. While in the bore, the bullet is spinning around its geometric center of form, which, due to imperfections in the bullet, may not be exactly the same as the center of gravity. Upon exiting, the bullet, free of the physical control of the barrel walls, transitions to spinning around its true center of gravity. It is this transition that sets up a slight wobble as the bullet shifts from rotating around one axis to the other. The wobble will diminish as the new axis of spin is firmly established.
@@rustyjohnson9558That's a really good explanation.
re: I have a hard time wrapping my head around going from unstable to stable"
That just shows that you have a good grasp on reality. A lot of bullets wobble somewhat after leaving the barrel but straighten out later. Sometimes a change in bullet design can make a difference, especially if it is a big change, like a large flat nose vs round nose, which is probably what happened here. Also modern manufacturing techniques have reduced the "out of balance" problems over what was seen with old bullets.
One of the US's top ballisticians (Jeff Siewert) already commented with: "Sorry guys, the wobble happens on virtually all shots; it’s the variation in initial wobble magnitude & direction that causes groups to non-zero in size."
Very occasionally, the core slips in the jacket and weird things happen (especially in armor-piercing bullets with tungsten cores). Otherwise, bullets tend to get more stable at distance until they slow down to near the speed of sound (transonic region) where changes in aerodynamic forces sometimes cause wobble, yaw, or other issues. A recent Hornady podcast discussed this when discussing twist rate.
Velocity I believe is more of a matter with overall pressure, bore/bullet friction and the pressure curve.... length of barrel too.
A twisting bullet might delay the movement of the bullet, too. So I'm sure it's also a factor... but not as much.
It wouldn't be the first time that a bone in an animal would deflect a bullet, within an animal too.
Thanks
Thanks Richard!!
Ron's opening line about bullet stabilization is correct. Full metal jacket bullets tend to tumble after impact and do not follow a straight path through the target. It is related more to the shape of bullet than to the rate of spin. All rotating objects become more stable the faster they are rotated. The only exception to that is if they are rotated fast enough to cause them to lose their shape or come apart due to centrifugal force and heat. Fort Scott ammunition sells bullets based on the design of the bullet cause them to tumble after impact. Any bullet that tumbles after impact is going to have its ability to penetrate changed. The story about bullets going to sleep is an old Goofy, not based in fact, fairy tale.
Berger bullets have a source where you can apply your bullet and twist rate and it will tell you how stable it would be instead of buying boxes of different ammo. Save you hundreds of dollars and headache.
A bullet leaving the barrel is akin to spinning a top. At the beginning of the spin the top makes a big ark or large concentric circles and eventually will stabilize in smaller tighter concentric circles. Same thing happens to your bullet flying through the air.
Good analogy, Shamoy. Thanks.
The spin imparted on a top is from a single point, the tangent of the pulling string. Spin imparted on a bullet is from the lands in the rifling which would be like many strings pulling from different directions with the same force on each string, which reduce the axial arc substantially, plus the surface the top spins on is much more resistant than the air.
However, a bullet has slight imperfections in weight distribution and is spinning at much higher rpm than a top. It spins around center of form while in the bore, but shifts to spin around true center of gravity when free of the bore's physical control. @@williamgaines9784 Same thing with the top, starts out spinning controlled by the string tangent, then shifts to find its own center of gravity when free of the string. Shamoy has it right.
@@williamgaines9784 Not all tops are launched by a string. A small finger spun top on a hard surface will have little friction, dare I say less than the friction of our atmosphere which is capable of reducing bullet speed by half in just a few seconds. All things being equally similar, a bullet launched from a rifled barrel does in fact take a moment to stabilize. Any military sniper will verify that greater consistently is achieved beyond the first hundred meters or so. I took me awhile to understand that until the top analogy was mentioned.
@@shamoy1000 If you think the surface that the top spins on has less friction than the air, then you should be able to strike a match by waving it in air.
Storied professional Don Heath was a professional's professional who used the 9.3x62 for everything, including some combat work. One of his observations was that the 375 H&H did not perform as well as his 9.3, notwithstanding the superior numbers that it generates. Some of this would probably be due to periods when poor bullets were often the only choice, however, this interesting data on twist rate may also suggest some answers.
His analysis generally of the 9.3 in his hands was that it was ideal for some of the softer skinned game, and that one could drill to the "vault" with it on on anything that might require it. The only thing it did not have was the ability to add some knock down on Jumbo. And for that he felt the 500 Jeff was the floor. He did recommend the 375 H&H for the average hunter, but that may have been because of the legal limitations on anything smaller than, and the fact it is a consensus opinion.
How many older cartridges would benefit from more research, twist changes, and higher BC bullets?
Browning improved the very old .270win by introducing a faster twist barrell in the xbolt rifle this year. Hopefully other companies research further into this and catch on as well.
@@bfitereastTX Excellent. More manufacturers should do this
@@reloadnorth7722 Many would. Individuals have been doing this for a long time. The issue is that you might need to use a longer action to fit the long bullets and that factory ammo would be an issue. Factory ammo is generally made to work in the worst case, ie slowest-twist. Some cartridges were designed around particular actions and their limitations, but could be improved for other rifles. For safety reasons, most improved cartridges are given a new name and sometimes changed enough that they can't be accidentally loaded into the old rifles.
You mentioned that this problem occurred with old kynoch style bullets. You did not mention how old the cartridge was. Could this be a problem with old powder going sour?
We got a bad powder lot of 4895 in our powder bags in our 105 MM Howitzer that lost range erratically. When we researched it we found that the powder lot was created in 1943! The Army got rid of most of the powder at the end of WW II. However, when new lots come in the Regs say they should be rotated with newer ones but, it doesn't always happen. We drew this lot of powder from Dugway from an underground storage area and that's how it happened.
Potential explanation. The bullet might have a small void that's unseen that changes the center of mass and or the center of gravity.
8.6 blackout enters the chat, 3.5in twist rate lolz. Honestly I have no interest i it for required bullet jacket for that fast twist. Fun podcast.
The 8.6 Blackout is optimized for subsonic speeds. That makes a big difference. Even if you zero at 100 yards, you will get over 30" of drop at 200 yards and over 40" at 225. Misjudging distance just a little can result in a miss.
Why is there no emphasis on the Greenhill formula? It has helped me considerably in reloading my .30-06 and other smaller calibers.
Why does the 30-06 stabilize anything from 110 grain all the way up to 220 hr? Never mind you answered my question as I was watching?
Bryan Litz:
"When my drill turns slow, the drill bit struggles to go into wood." That 8.6 BLK spins fast, maybe 25m to 150m it works well. Now, how do we fast twist that 300WSM concept. Or do we neck the 416RM down so that you can 400grains with twist rate. Just a thought. The drill needs to spin that 400grain weight fast enough between 25m to 200m
What about the 35 Whelen with a 16 twist in the Remington 700? I've read that an all copper 225 or 250 grain bullet wont stabilize under say 4500 ft above sea level.
Copper alloy bullets are less dense than cup and core, so they will be lighter if they are the same shape. A copper bullet will be about 20% lighter than a comparable cup and core but might actually penetrate deeper, depending on design. Barnes has 35 Whelen loads with 180 and 200 grains bullets which correspond to 225 or 250 grain cup and core.
On pointed and round nose bullets, it doesn't take much of an angle to cause a projectile to alter its trajectory. There are documented cases of individuals being shot in the head with both hand hund and rifles where the projectile deflects slightly and follows the skull plate under the skin until it exists the skin on the back side without ever penetrating the skull. I suspect this is what is occurring when the bullets yaw points its axis more tangent to the surface at the moment of impact. This will be exaggerated with both larger diameter bullets, and older bullets that were not as consistent and uniform as what we have available today.
I was watching a video on the 8.6 Blackout on Garand Thumb and they were punching subsonic 338's through 4 feet... not inches, but feet of ballistic gel. 1-3" twist. Why?
Perhaps this conversation Ron is having about twist rate. Maybe this is why 30-06 shooting "accelerators" they offer poor accuracy.
The twist of most .30 cal that used accelerators is very similar to the .22 cal barrels that would use the bare bullet, so it is not the rpms as much as the sabot is imperfect and it magnifies any imperfections in the bullet that might have otherwise been corrected by direct contact with the barrel. The .22-250 is not pushing the 55 gr bullet much slower than the accelerator.
That other saboted projectiles do better could be that the ratios of core diameter to sabot diameter to overal length is not as great as in the .30 -.22.
I've a 1-9 twist in my Savage Axis 223.
It could be that a bullet, especially a longer bullet, flexes slightly when exiting the muzzle, just like an arrow does, and eventually stabilizes further on its trajectory. This could be caused by the rifling itself as it disengages from the bullet. First the frontal portion followed by the base.
Interesting idea, Tim, and not as wild as it first might seem. Bullets do expand slightly while moving down the barrel and they can/do distort somewhat in the barrel, but I've never heard that they flex longitudinally like an arrow. They do emerge with the tip often rotating off their center. This "yaw" usually settles down after 50 to 100 yards.
How does this equate with the 8.6 Blackout and a 1 in 3 twist?
Why can't we compare slower cartridges like a shotgun. Let's say a sabot slug. Shotgun chokes are there to reduce the spin. Big ball slugs can be delivered through a smooth bore. Sabot slugs on the other hand have a front and tail heavy shape. Newer variations of sabot slugs are using more modern day pistol projectiles.
We can also use even slower moving projectiles to determine this. Your typical archery arrow stabilizes the further down range it goes. The spin rate also increases. The most recent theory of archery arrows is F.o.c. (forward of center) balance.
I believe bullet construction and shape determine the required twist rate. Longer b.c. bullets make more contact with the lands. The heavier bullets are also using increased pressure to excel them.
I believe this is why each platform will perform different with different ammo and load. Some styles of rifling are more forgiving. 5R twist has more land surface area than a 6R.
Again compare archery arrows. The short arrow stabilize sooner. And 4 feathers add more twist over a 3 feather construction. The energy with a heavier arrow or a light variations has completely different accuracy.
Finally....there is no all around perfect combo. That's why it's called precision shooting. All factors for one specific target.
The old Mausers had faster twist than some modern rifles. I think some pistols may have not enough twist with longer slugs . My old swede only one weight , 120 gr did I see keyhole the target.
We should be using a progressively faster twist rate barrel. It starts off with a very slow twist and ends with a very fast twist.
Like a Carcano M91, etc.
Rifles like the Carcanos did this, but it apparently has little positive effect with rifle-caliber bullets. Companies like Bartlein and Krieger will sell you one, but even they admit it does not have a significant affect on accuracy. The vast majority of their competition barrels use normal rifling twist. Gain-twist is apparently very important with some cannon calibers, though.
When a youtuber with decades of reloading experience (not me) claims that cartridges like 6.5 CM or others with 1:8 twist, and using the really long bullets like the Accubond LR are very hard to load for, the question still is unanswered: Why? Not enough jump when seating the bullet? Too fast? Too high of twist rate? Maybe long range (1,000 yds) loaded cartridges don’t work optimally at close range with longer bullets? Maybe some slo-mo footage could shed some light on what’s really going on. Enquirin’ minds wanna know.
6.5creed is simple to reload as easy as the 308 or 30-06
ABLRs have been great in my various 6.5s, 7s and 30 cals.
@@warrengreen3217wrong 6.5 Creedmoor is the hardest cartridge i have ever loaded for
@@awsomedude12345678 not for me but I full size and seat bullet on cannalure
@@warrengreen3217 do you crimp?
The required twist rate is determined by the LENGTH of the bullet, NOT THE WEIGHT. Longer bullets REQUIRE higher twist rates. We only see over-stabilization when the twist rate exceeds what is required by the length. Like it or not, needle-like bullets at higher twist rates are the future. The reason we have not had them before now has nothing to do with accuracy. If that were the case, the faster twist-rate rifles would be less accurate, and we do not see any indication of that.
We have not had higher twist rates due to bullet construction and cost. Higher twist rates wear out buttons faster, and lead can only hold up to a specific RPM, depending on the thickness of the copper jacket. However, with the advancement of solid copper bullets, we can now move beyond what would typically blow a lead bullet apart in flight.
Wrong. There is a center of pressure vs center of gravity issue. Its nothing to do with length. Think about archery arrows. They dont fall end over end when fired. They're long and light. Revise your belief structure with science. Go to Hornady youtube and look for internal ballistics, bullet construction, and other similar episodes. They have actual ballistic engineers on their show.
@@neglectfulsausage7689 Arrows have fletching at the rear to create drag for stabilization. Pellets do the same thing with their skirts. As a result, they don't require spin to stabilize. You have to fully understand all the science to realize I am correct. Any ballistic engineer will agree with me. God bless.
P.S. One of Ron's next episodes had a guest who confirmed what I said here, but not directly. I will see if I can find it.
@@coreymoyers5771 No, the fletching moves the center of pressure behind the center of gravity. try again.
@@neglectfulsausage7689 John McAdams was mistaken, but this guy was spot on. ruclips.net/video/qjeyH_0X6Wg/видео.html
All guests can't be a home run. Ron may have even realized John was incorrect then but didn't want to point it out.
Instead of a 375 H&H, use a “rifled barrel 12 gauge shotgun” with a 1-4, 1-6, 1-8, or 1-10(yes Vortex makes one) scope using “brennekeusa” Brenneke SLUGS for hunting African Water Buffalo or Grizzly protection.
This sounds more of a terminal affect ie peneration n expansion based on RPM or Twist Rater..
Wonder if anybody has done gel test with different bullets n weight calibers etc n twist rates.
It does seem to me that if the twist rate were absurdly high, it would lead to higher pressures as the bullet would have more resistance from the lands in the barrel. That higher pressure surely could affect accuracy.
The twist wasn't absurdly high in the example, but pressure is controlled/limited by SAAMI specs per cartridge stated as MAP, maximum average chamber pressure. This can vary shot to shot and there's a large, built in fudge factor, but changing twist from 1-12 to 1-10 or even 1-8 isn't likely to radically increase pressure. And high pressure doesn't necessarily ruin accuracy. Many cartridges are rated 65,000 psi and just as potentially as accurate as those rated 50,000 psi.
I thought it was well known that light bullets don't like high twist rates.
So the 375 that didn’t penetrate the buffalo skull at short range was solved by going with a longer, heavier bullet?
To conclude that the root of the problem was too much gyroscopic stability makes no sense to me…
By switching to a longer, heavier bullet… the dominant change is an obvious increase in sectional density… which increases penetration potential.
IMO the solution to an inadequate penetration problem at short range is:
1) use bullets that retain most or all mass but have reliable controlled expansion.
2) choose longer, heavier bullets with a high sectional density… high sectional density yields greater penetration.
Trevor, surely you are right about the longer, heavier bullet increasing penetration potential, but I'd argue as a solid (FMJ or monometal) rather than controlled expansion, although some of our best CE bullets can and do penetrate ridiculously well. Such was the little 270-gr. Shock Hammer I used to brain a buffalo with Zambezi Delta Safaris last year. Despite its nose petal shedding design, that Hammer drove through the brain and into the heavy, thick Atlas bone at the back of the skull, which it cracked, but failed to punch through. Hardly mattered because that bull was dead on arrival. As for that gyroscopic stability issue, I think Robertson was arguing that the initial yaw of the bullet nose contributed or led directly to the off-course penetration. Because bullets, regardless the twist rate, emerge from muzzles with variable yaw, they can strike close targets with the nose/tip quite a bit off axis. This means the impact/friction of hide/muscle/bone on one "side" of the nose directs the entire bullet off its flight path. Rather like striking a branch. Hunting lore is replete with bullets ending up in strange places far from their initial line of flight. But I agree with you that "too much gyro stability" was not the issue. Less gyro stability would likely only increase the yaw, I would guess. But I could be wrong. At any rate, a longer, heavier bullet would/should increase penetration and any degree of yaw. Thanks for offering your studied opinion.
@@RonSpomerOutdoors Wow Ron! Thank you for the comprehensive reply!… The specific bullet type that I had in mind when I suggested a long and heavy weight retaining controlled expansion bullet for achieving adequate penetration on beastly bone was the barnes TSX… these are the non tipped copper monos with the hollow point. But… truth be told I am definitely the student here as I have zero experience hunting giant African game like cape buffalo or elephant!
Regarding the issue of too much gyroscopic stability… It is my understanding from listening to ballistics gurus like Jayden Quinlan and Bryan Litz… that cheap conventional lead tip cup and core bullets can suffer from degraded accuracy at high rates of twist. The issue is that flaws in the radial inertial concentricity due to uneven jacket thickness or lead density or uneven tip shape cause exacerbation of the yaw of repose when the bullet hits the air resistance and goes through its wobble cycles at higher rates of spin… so… higher spin can cause more yaw in cheap bullets with poor cross sectional or radial balance.
Eeek… I hope that’s not too much word salad.
Cheers!
This would be Caused by bullet jump the bullet is Microscopically hitting the lands and grooves at a odd angle. manufacturer's specifications are on average smaller than most gun chambers, on Purpose for magazines feeding. I bet if one was to hand load that 375 to the tightest of tolerances that Initial Wobble would be minimized
What is differance between 20inch barrel 1.8 twist and 26inch barrel 1.10 twist in same calibre ? 2.5 twists in 20 inch per barrel lenght anf 2.6 twist in 26 inch barrel..?
It doesn't matter. The rate of twist is consistent regardless barrel length. Rifling that twists at a rate of 1 turn in 8 inches spins a bullet the same in an 8" barrel, 18" barrel, 4" barrel, 40" barrel. In a 26" barrel with 1:10 twist rate the bullet would complete 2.6 complete turns (not twists) while still in the barrel. With 1:8 it would complete 3.25 complete turns. Big deal. The bullet's rate of turning or spinning around its axis matters when it's free of the barrel and in the air. Its gyroscopic motion (spinning) stabilizes it more or less nose forward so that it does not tumble.
Hi Ron, that is what i dont understand...i meant 1.8 twist in 20 inch barrel the bullet makes 2.5 rotations...so it is less than a 1.10 twist in 26 inch barrel that a bullet makes 2.6 rotations before leaving the barrel...if increase lenght of 1.10 twist barrel rotation of bullet can also go up to 3.25 rotations like a 1.8 twist 20 inch barrel.. thanks
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Over-stabilization becomes an issue at longer ranges. Bullet angle of attack vs ballistic trajectory.
For artillery that is shooting at high elevation that is correct. For most rifles at distances less than a couple miles, not so much. In Bryan Litz's books about long-range marksmanship with rifles, doppler radar showed that faster twist tends to help at longer distances. The faster spin helps the bullet "go to sleep" quicker (as Ron said), so it has less wind resistance and stays faster. Also, as the bullet slows into the transonic range, faster spin keeps it point-forward. Many bullets lose stability as they approach the speed of sound and yaw wildly.
It’s interesting information but to me it really doesn’t make a difference when it comes to generalized hunting with the cartridges that we are most familiar with, I also found it interesting that Ron months ago talked about someone hunting in Africa years ago with a 7 mm Mauser killing so many elephants with one shot, and now it seems in conversation That more weapon is actually needed and why,
Some of this is due to bullet construction and velocity. If you fire a bowler ballistic tip at 3000 FPS out of a 7mm rem mag and shoot a bull elk at 15 feet you will get wayyyyyyyyyyy less penetration than you would at 400 yards. This has NOTHING to do with twist it is simply velocity being too high for that bullets construction on the very dense target that elk are. But if it is a case where you are shooting solids then yes it probably a stability issue. If the projectile doesn’t hit square to the trajectory path then it may rumble or curve in the target providing less penetration than at a slightly greater distance where the bullet is more concentric in flight. So yes there is a nice ideal twist rate for a given load. But this is probably way oversold especially for North American big game hunters. This is 99% a dangerous game issue. In that case definitely worth considering.
Sounds like it's an issue with the difference between the material your bullet is traveling through. Bone will produce issues the flesh doesn't.
I wonder how similar this is to the behavior of bullets in water, in the sense that larger bullets slow down faster vs. smaller bullets. I am thinking in terms of something like a fluid dynamics problem, or how space craft will bounce off the atmosphere if they hit at the wrong angle or a bullet will skip off water surface due to the water surface tension. That extra energy, is going somewhere as the bullet leaves the barrel, hits the air, and is pulling on the bullet in the wrong direction, creating drag like a wirlpool suction effect, to slow the bullet down, until it stabilizes. That is probably overly simplistic. Just a thought.
Is there such thing as reversed/clockwise rifling?
Yes. It really doesn't matter except when you get to a long range where spin-drift becomes an issue.
I see the 3rd Infantry Division patch. We shall remain, sent me sir. 1st of the 15th Infantry. 1974-1976.
Physics state that the faster you rotate any object including a out of balance tire the more stable it becomes. You have to obey the speed limit when you're driving a car. If you kept rotating a tire fast enough the rotational velocity can exceed the acceleration outward due to a imbalance moment of inertia. When that happens a out of balance tire will become more stable but when it's on a car it has to obey speed limit or you get a ticket from the cops and cars can only spin wheels as fast as the car can go.
I have wondered if high twist rate accuracy issues with lower weight bullets might have something to do with bullet quality. Bullets are typically considered homogeneous. But what if the center of mass is slightly off of the center axis of the bullet? Maybe from a small nick on the bullet casing. Would this slight rotating imbalance become increasingly noticeable at higher spin rates, similar to an automobile tire spinning faster on an axel? I don’t believe there are perfect bullets, but some are likely better than others. Increases in rotational speed above what is required for stability might worsen rotational imbalance issues. I have no factual data or reference to support my suspicions.
Who was that famous writer back in the 50tys and 60tys that hunted elephant with 270 .Elmer Keith?
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@@bobbob8229 yes and his wife, so a woman can drop elephant with a 270 but a man wimpy uses a belted magnums. Read up on some of those old timers that could kill big game with shot placement instead of putting a bunch of holes in and around the arse of an animal. If you watch Bill moles the Alaskan guide he had a German man drop a 10 foot plus brown bear with a 270 and he has had clients with 375h and h and empty their gun twice because they thought they were a man. Nope
@@bobbob8229 there is a man here in Blanco tx back in his glory days killed some of biggest elk in Colorado with a 222 Remington, mid 90s now. Just did it to prove it could be done. Shot placement is the game. If you want to talk about numbers Wilfred wastal out law hunter, probably 60ty bucks a year off the king ranch. Model 99 savage 243 80ty grain bullet, my brother inlaw Harlow kibbe Model 70ty Winchester 243 80ty grain bullet I've seen him drop deer pushing and past 500 yards. Neck shot every time, I've killed many deer on the king ranch 16 inch savage 340 in 222, when you have to run it's light, and believe me when you hear the hammer of a colt cock you are not going to say good morning! You put trees mesquite and motts of mesquite between that colt and your ass,it's happened and have witnesses.
Ron and/or John, can you comment on the new 8.6 Blackout and twist rate? There’s a video out showing the 8.6 with a really fast twist-maybe 1 turn in 3"- and they were claiming it makes a big difference on the terminal performance. Specifically, it makes a a much larger permanent wound cavity. Thoughts?
It helps monolithic bullets open up faster and wider but can cause fragmentation and core-slip issues with cup and core. The effect seems much more important for subsonic ammo that is traveling too slow to cause wounds from the temporary cavity.
I thought that its actually the amount of the bullet actually engaging the rifling
I don't think so. Bore rider bullets engage rifling with a small , raised ring along the bore diameter shank. Two of these, fore and aft, might increase accuracy, but one is enough to impart spin.
1in 8 is perfect for a 16” ar in 556
I’ll put in my two cents worth, but the problem is more leaning somewhere else than where everyone is pointing; I would seriously look at the crown of the muzzle. If you’re having these issues if you get gas escaping from one side of the base more than the other as the bullet exits, you’re going to tilt the base of the bullet generating a wobble, The severity of the wobble determines the distance beyond the bore at which point the bullet will re-stabilize, directly impacting group size. This effect is more pronounced with spire point bullets Because of the change in weight decreasing toward the point. Most of my hunting is with pistols, a lot of it in the old days with the round nose Before realizing they are not very effective for hunting animals due to greatly reduced tissue damage as that round nose squeezes its way through tissue, without making much of a wound channel until the bullet starts to tumble, which, after many many deer and hogs, a round those bullet is almost guaranteed to tumble, which, depending on the thickness of the animal could be a good thing, because of a larger, wound channel occurring at that point, but on narrower animals The tumble may occur as it exits the far side, creating very little damage to organs prior to a long, tracking job. I learned long ago that flat nose bullets tend to penetrate media and a very much straighter nose, first attitude and straight line penetration; while violently slapping tissue outwards creating a much larger, permanent wound cavity. We can “one-up” this by milling a slight concave flat meplat, get even better penetration, the dynamics of which I am not quite understanding yet. In all of this, I’m talking about 44 and 45 caliber magnum handguns using hardcast lead Flat-nose bullets On feral hogs. I’m going to fully assume any non-expanding bullet of the same nose design would offer the same advantages in rifle calibers, as big as you want to go. Watching slow-mo footage Of bullets exiting barrels, it appears to me that the more equal weight from the trailing edge to the meplat Inherits less wobble at the bore departure than can occur with longer more tapered bullets. Meaning a wadcutter style bullet more possibly have less wobble than anything short of that I don’t know what they make for African solids because I don’t see me making a trip to Africa. Maybe some of y’all know if they make bullets (solids) of this nature. Just to quickly add the bullets that I am old are so hard they do not expand, but it’s difficult to tell the difference between that, and a hollowpoint, as far as damage is concerned, and deflection is much less with the solids at least on the Even really big hogs. I have to admit it took me a half a century of Bullet, casting, and hand loading to learn this.
NOW 8.6 BLACKOUT WITH 1-3 TWIST HAS 500,000 RPM subsonic goes through 3 ballistic gel blocks ! Explain this?
After listening to this, I remain thoroughly unconvinced that you can overspin a bullet
In my humble opinion it is much more about deflection at higher speeds. I had better penetration with reduced bullet speed in moose at close range with the same projectiles. The old rounds with speeds between 2200 and 2400 ft/sec penetrated like a charm, mostly in a straight line. Make them faster and every little tissue difference in the animal deflects the projectile from its original path! Initial shock is higher when you get closer to 3000 ft/sec, which is evident in the drastic dropping of many thin skinned species. Gel tests are in this respect misleading, since they do not offer the tissue variability found in animal muscle tissue including sinews and fatty areas. Twist rate is important regarding bullet length but has little to do with the discussed penetration problems. It all comes down to bullet speed.
These Ron Spomer episodes are getting some serious homoerotic vibes... and I like it!
How about I build a custom 308 with 24” barrel with a 1:9 twist. Would it over stabilize a 130?
Just don't shoot a Cape Buffalo with it and you should be fine! 😀
@@jfess1911 I wouldn’t dare.
@piercer2 Seriously, though, overstabilization is not really an issue. A higher spin rate should help with stabilization, if anything. The main issue is that it is possible to spin thin-jacketed bullets so fast that they come apart in the air, but I have never heard of it happening with a setup like yours. You might even be able to find out the max allowable spin rate for your particular bullet from its maker.
I don't know that the original core problem was clearly confirmed here.....
Ron I believe I will get my stability info directly from Bryan Litz or Jayden Quinlan.
Those are unimpeachable sources. Bryan is the zen master of ballistics.
How does this information apply to 5R rifling? Is that even a factor?
I doubt it. 5R just reduces bullet engraving/squeezing because the lands are more sloped into the grooves and opposite a grove rather than opposite another land. So, reduces bullet deformation potentially increases accuracy. Less barrel fouling is also claimed.
If you can't dazzle them with brilliance dazzle them with bullshit!!!!
3rd I.D!!!
Not only is the bullet affected by the twist rate, but it affects the barrel vibration too. Keep that in mind when thinking about the accuracy, and bullet yaw too...
That was a lot of "think" and just not a lot of "know"
It's all about balance !
Velocity and twist rate are linked. The faster a bullet spin the greater the wound channel: very useful for taking long shots when bullets drop below 1800fps it helps a great deal as expansion or fragmentation is minimal but too much spin is not that useful at close to "normal" hunting range as it can be very destructive on game.
That's why you usually found the 7-08 with 9 to 9.1/4 twist rate and 7 RM with 9.5 to 10 twist, the later being a much faster cartridge !
A 300 GR bullet out of a 375 will not shoot but 2500 FPS i think that a 270 GR bullet might do better it will go 2700 FPS.
So if these old style bullets had that problem in the 375,surely it would have reared its head more than twice in the more than 100 years of shooting large dangerous game in Africa with the 375 h h?! Huh?