I am an auto mechanic by trade and I believe what can happen with a charge that leaves a lot of empty space in the case is the phenomenon called 'detonation'. Which is same as it happens inside the cylinders of your car's engine and causes that familiar knocking and pinging sound. Instead of a smooth progression of a 'flame front' from one end to another, the primer flash ignites the powder from several places at once and the pressure fronts just collide inside the chamber, the stuck bullet in the rifling may or may not amplify the pressure spike. The main cause is that the several flame fronts collide inside the casing and thereby causing a pressure spike that is seemingly unattainable by a low charge. Same thing happens when you use a low octane gasoline in a high compression car engine, the air fuel mixture spontenously combusts as it gets squished inside the cylinder space and several flame fronts collide. Or if the cylinder is extremely carboned up and the carbon ambers act as a secondary spark plug and creates a opposing flame front which collides with the intended flame front inside the cylinder. Loud pinging is the familiar sound as if someone is whacking on the block with a sledgehammer, which is pretty much what happens...
Whale Oil Beef Hooked! You're the first that put an example of how it happens with a low charge, not just a warning and end result examples. (which are good, as it's always good to heed warnings, but even better with the methodology as to how it happens, behind it). Cheers mate.
So glad I came across this video when searching on google because this is exactly what happened to me. I had to change my preferred tried and tested powder due to EU regulations in the UK and erred on the side of caution with the minimum recommended charge when loading up a first batch. The results were horrific! I popped primers and a couple of the cases even imprinted on the brass when they hit the breech face. I have been unwilling to revisit the load up until now, as I couldn't work out what was going on. I know you originally posted this in 2016 but many thanks for taking the time to do so because it really has helped me a lot!
If you get the powder volume over the primer it won’t be an issue. Figure out the volume available with your seating depth and then what volume will cover the primer
Regardless of some people's denials that this can happen, I have played with reduced charges a lot and I believe it can. I do not think it happens for the specific reason given here in this video but I think there IS a danger..specifically in slower burning (usually!) powders with lots of empty space in the case. All of the major powder manufactures recognize that this is a danger despite disagreements on the exact reason why. Modern Reloading by Richard Lee speaks about this and his rules for staying out of trouble when reducing charges. Whether or not his approach is safe, I cannot say for sure but I haven't had my face blown off yet! We will see! Anybody who questions that reduced charges can have strange effects, can load a lower volume charge and see how positionally sensitive they are, by holding muzzle up prior to the shot over a chronograph, then down prior to the next. I have seen hundreds of fps variations through a chrony by doing this with reduced charges..that is a pressure effect and a big one. So based on that alone, I would be very careful before sailing into reduced loads uncharted, "there be sea dragons!"
It absolutely is a real thing. Seen it and the data to measure the pressure (over 200,000). The guy was using No. 9 to fire form brass with some weak loads and went too low. The cartridge implodes, so sometimes you might find dents in a spent case if you are playing with fire.
some guy on a social media platform just blew a pistol up, blamed the barrel but went .5 below starting. I told him to just put it down and walk away. He even has load data to use and still went low. He said he's been using 5.0 in a different pistol and no issues when the starting point is 6.9. Darwin winner people
Your picture was helpful but I think the explanation was wrong with key being slow burning powder. With full case capacity,, burning powder has an area equal to Пr2 of the case, which starts at the base and burns consistently towards the muzzle because the pressure pushes the powder and keeps it mostly moving down the barrel. With low powder you have a burning surface area equal roughly to the major cross sectional area. This leads to a higher initial pressure which spikes even higher because the powder burn is perpendicular to the bore axis causing the powder to churn and deflagrate at a much higher than normal rate.
This makes a lot of sense, I was questioning his explanation. Every bullet I shoot is "jammed" at some point. Could be the reason faster burning powder might make more of a punchy thud noise, not so much that the burn rate is faster but because it ignites faster.
Hi there. This can happen and did happen to me personally. My Wildey Survivor damn near bit the dust and took my hand with it due to a mistake where a half charge of blue dot was loaded into a .45 Win Mag. I'm going to be posting a video to my own RUclips channel analyzing the failure. Luckily, only minor cuts to my hand and the gun was repairable!
This dawned on me while loading minimum charges of BLC2 vs.minimum charges of varget....varget filled the case quite well, and blc2 left a lot of room......blc2 was leaving heavy soot marks on the case....thanks for clarifying a possible reason why...
Years ago i picked up a 7rum it just came out no reload data was available, the only recomended powder was retumbo at that time, 88grns was the min start. So i loaded up a few rounds a 160 grn bullet and fired! The rifle sounded like a artillery canon jumped out of the rest all the high pressure signs were there get this 0 drop at 500 yards. Took the rifle in to a gun smith to check it out could not find anything wrong with the rifle. I could not find anybody with a answer to my problem. Many years later i ran into a old school reloader and told him my problem, he told me all rifles are different and the starting load of 88gr was way to hot for my rum drop the powder charge a few grns and try it again. I dropped the charge 3 grns and fired! The rifle dropped down to normal but was still hot, i ended up at 82grns when all pressure sighs went normal. Shoots great now. Ran into another guy with a 7 rum also his rifle wants more he is using 92grns retumbo go figure. Its been ten years now much more data available for the 7rum. Imr 7828 works great, i wonder what the velocity was the first time?
Well stated. If you can find P.O. Ackley's books on ballistics he covers pressures and how it affects bullet performance and hazards extensively. I believe he even covers this issue thoroughly in his 2 volume set.
Just watch this video about reduced lows with slow burning powders. At one time I shot cast bullets silhouette, if you know anything about cast bullets loads, they are somewhat reduced when compared to jackted bullets. Two of the all time greats, namely P.O.Ackley and Jack O'Connor write about this; Ackley in his 23rd printing of "Vol 1 Handbook for shooters & reloaders" and O'Connor in his book "Blow-ups with Slow Burning Powder". I STRONGLY recommend any serious shooter & reloader get and read both of these books.
I’m dealing with a load that is not seating at the neck getting blackened brass up into the shoulders. I’m to max load by the nosler book now. But all advise I’m getting is pressure is to low yet? Primers don’t show high pressure.
I need some really low velocity 9mm FMJ for ccw. Jersey banned expanding ammunition of all types for concealed carry. I want fmj that will fall between 12-18 inches of gel bloc penetration (FBI spec)
We used a low charges for 9x19 for sport trainings reason (ipsc) for many years. Vihta N320, N340, Fiocchi Frex-Green powders. // but with heavy bullets: 147-150grn.
Half a cigar.. yes the low powder load is a problem, but that is not the cause.. what is happening is that the powder is slammed against the base of the bullet and then detonates.
i have a 270 wsm it needs a low charge or it bolt locks on the min in my book i had some reloader 17 the maker of it told start and max load it worked! only in that firearm ( i asked a pro he went nutso and made a video and blamed me with overloading and stuff like that ps i checked books and makers and even make of barrel too) if 3200 ft is equal a factory load i cingo it after balistics was way off the same load in 6.8 western has 2850 there nearly same rifle it odd i went for a 6mm creed more the guy had a 6.8 western there the 270 was a built nightmare( my internet emails is crap the backer for testing called on land line he why we not hear?) i got ok for one then he was off i got ok a few days later i coming to get it! ok my hunting was a mess! snow and then cold and then a call for help a hunter fell! so i got a bow and extending time still!
My max load is 41.0. Minimum load is 38.0 in the manual. Your telling me to drop 10% from max load ending up at 36.9? Thats more than 1 grain under the minimum load in my manual
Most reloading manuals recommend starting 10% below max load. Depending on the cartridges or powder being used that 10% can drop below the minimum charge listed. If that’s the case, I would start off closer to the minimum charge and work my way up while looking for any pressure signs. Additionally I find that starting somewhere in the middle usually works for a good starting point.
Some loads have a much smaller range too, so the 10% rule isn’t universal. Look in the manual and you’ll see lots of examples where one powder can be used across the whole table and another is only listed for 2 or 3 weights
Vaughn Precision I mean for instance if you wanted to make a sub sonic .243 load (which would be silly buy whatever) or a load that wouldn’t burn out your barrel or give as much kick is there any way to go below the minimum value and still be safe? Maybe like a filler that mixes with the powder?
Yes there is. Shotgun reloaders frequently do this for skeet and trap shooting. Any "filler" can assist with this and many use cotton balls but you have to be careful with that as variations in amount of filler can alter pressures also. Check into it and you will find people reloading with fillers to prevent this problem. Reloading has and will always be dangerous so do your own due diligence regarding this.
@@vaughnprecision what if you packed the empty area with a foam or cotton, to keep all the power pressed firmly against the wall, so that way even if your shooting down into a drain whole, or just straight down from a hight. You would have primer igniting to empty space.
I guarantee that you are one of those people who always say start 10 percent and work up.. you really didn’t tell us anything. And if your theory is correct how does shooting lead with pistol powder work… not at all being smart. God bless you and good luck
I watched Fortunecookie, then this. I like both, but didn't pick up on the arc flash moving the bullet into the lands which plugged the bbl until watching this. Thanks both of you guys for the explanation.
I am an auto mechanic by trade and I believe what can happen with a charge that leaves a lot of empty space in the case is the phenomenon called 'detonation'. Which is same as it happens inside the cylinders of your car's engine and causes that familiar knocking and pinging sound.
Instead of a smooth progression of a 'flame front' from one end to another, the primer flash ignites the powder from several places at once and the pressure fronts just collide inside the chamber, the stuck bullet in the rifling may or may not amplify the pressure spike. The main cause is that the several flame fronts collide inside the casing and thereby causing a pressure spike that is seemingly unattainable by a low charge.
Same thing happens when you use a low octane gasoline in a high compression car engine, the air fuel mixture spontenously combusts as it gets squished inside the cylinder space and several flame fronts collide. Or if the cylinder is extremely carboned up and the carbon ambers act as a secondary spark plug and creates a opposing flame front which collides with the intended flame front inside the cylinder. Loud pinging is the familiar sound as if someone is whacking on the block with a sledgehammer, which is pretty much what happens...
You are right. Powder burns on large surface and in short period of time produces critical pressure.
then why doesn't that happen with a 22lr ?
Whale Oil Beef Hooked! You're the first that put an example of how it happens with a low charge, not just a warning and end result examples. (which are good, as it's always good to heed warnings, but even better with the methodology as to how it happens, behind it). Cheers mate.
Crows 2332 thank you ..!! Hope it helps
Thanks, yes. Definitely reinforces it.
So glad I came across this video when searching on google because this is exactly what happened to me. I had to change my preferred tried and tested powder due to EU regulations in the UK and erred on the side of caution with the minimum recommended charge when loading up a first batch. The results were horrific! I popped primers and a couple of the cases even imprinted on the brass when they hit the breech face. I have been unwilling to revisit the load up until now, as I couldn't work out what was going on. I know you originally posted this in 2016 but many thanks for taking the time to do so because it really has helped me a lot!
If you get the powder volume over the primer it won’t be an issue. Figure out the volume available with your seating depth and then what volume will cover the primer
Regardless of some people's denials that this can happen, I have played with reduced charges a lot and I believe it can. I do not think it happens for the specific reason given here in this video but I think there IS a danger..specifically in slower burning (usually!) powders with lots of empty space in the case. All of the major powder manufactures recognize that this is a danger despite disagreements on the exact reason why. Modern Reloading by Richard Lee speaks about this and his rules for staying out of trouble when reducing charges. Whether or not his approach is safe, I cannot say for sure but I haven't had my face blown off yet! We will see! Anybody who questions that reduced charges can have strange effects, can load a lower volume charge and see how positionally sensitive they are, by holding muzzle up prior to the shot over a chronograph, then down prior to the next. I have seen hundreds of fps variations through a chrony by doing this with reduced charges..that is a pressure effect and a big one. So based on that alone, I would be very careful before sailing into reduced loads uncharted, "there be sea dragons!"
It absolutely is a real thing. Seen it and the data to measure the pressure (over 200,000). The guy was using No. 9 to fire form brass with some weak loads and went too low. The cartridge implodes, so sometimes you might find dents in a spent case if you are playing with fire.
This makes good sense, I can see how dangerous that could be. This is very important thanks so much
some guy on a social media platform just blew a pistol up, blamed the barrel but went .5 below starting. I told him to just put it down and walk away. He even has load data to use and still went low. He said he's been using 5.0 in a different pistol and no issues when the starting point is 6.9. Darwin winner people
Your picture was helpful but I think the explanation was wrong with key being slow burning powder.
With full case capacity,, burning powder has an area equal to Пr2 of the case, which starts at the base and burns consistently towards the muzzle because the pressure pushes the powder and keeps it mostly moving down the barrel.
With low powder you have a burning surface area equal roughly to the major cross sectional area. This leads to a higher initial pressure which spikes even higher because the powder burn is perpendicular to the bore axis causing the powder to churn and deflagrate at a much higher than normal rate.
Very interesting point 👍
Yeah, Tim, it's right.
Tim is absolutely right.
This makes a lot of sense, I was questioning his explanation. Every bullet I shoot is "jammed" at some point. Could be the reason faster burning powder might make more of a punchy thud noise, not so much that the burn rate is faster but because it ignites faster.
Hi there. This can happen and did happen to me personally. My Wildey Survivor damn near bit the dust and took my hand with it due to a mistake where a half charge of blue dot was loaded into a .45 Win Mag. I'm going to be posting a video to my own RUclips channel analyzing the failure. Luckily, only minor cuts to my hand and the gun was repairable!
This dawned on me while loading minimum charges of BLC2 vs.minimum charges of varget....varget filled the case quite well, and blc2 left a lot of room......blc2 was leaving heavy soot marks on the case....thanks for clarifying a possible reason why...
Years ago i picked up a 7rum it just came out no reload data was available, the only recomended powder was retumbo at that time, 88grns was the min start. So i loaded up a few rounds a 160 grn bullet and fired! The rifle sounded like a artillery canon jumped out of the rest all the high pressure signs were there get this 0 drop at 500 yards. Took the rifle in to a gun smith to check it out could not find anything wrong with the rifle. I could not find anybody with a answer to my problem. Many years later i ran into a old school reloader and told him my problem, he told me all rifles are different and the starting load of 88gr was way to hot for my rum drop the powder charge a few grns and try it again. I dropped the charge 3 grns and fired! The rifle dropped down to normal but was still hot, i ended up at 82grns when all pressure sighs went normal. Shoots great now. Ran into another guy with a 7 rum also his rifle wants more he is using 92grns retumbo go figure. Its been ten years now much more data available for the 7rum. Imr 7828 works great, i wonder what the velocity was the first time?
That’s not what this video is about.
Well stated. If you can find P.O. Ackley's books on ballistics he covers pressures and how it affects bullet performance and hazards extensively. I believe he even covers this issue thoroughly in his 2 volume set.
Just watch this video about reduced lows with slow burning powders. At one time I shot cast bullets silhouette, if you know anything about cast bullets loads, they are somewhat reduced when compared to jackted bullets. Two of the all time greats, namely P.O.Ackley and Jack O'Connor write about this; Ackley in his 23rd printing of "Vol 1 Handbook for shooters & reloaders" and O'Connor in his book "Blow-ups with Slow Burning Powder". I STRONGLY recommend any serious shooter & reloader get and read both of these books.
Is this effect worse on bottleneck cartridges than straight wall?
I'm thinking straight wall is safer maybe?
I’m dealing with a load that is not seating at the neck getting blackened brass up into the shoulders. I’m to max load by the nosler book now. But all advise I’m getting is pressure is to low yet? Primers don’t show high pressure.
Thank you very much for that informatio.
I need some really low velocity 9mm FMJ for ccw. Jersey banned expanding ammunition of all types for concealed carry. I want fmj that will fall between 12-18 inches of gel bloc penetration (FBI spec)
We used a low charges for 9x19 for sport trainings reason (ipsc) for many years. Vihta N320, N340, Fiocchi Frex-Green powders.
// but with heavy bullets: 147-150grn.
@@nickbalashov1780 does it cycle ?
I wonder if a low charge could also lead to a lot of smoke
Half a cigar.. yes the low powder load is a problem, but that is not the cause.. what is happening is that the powder is slammed against the base of the bullet and then detonates.
Well presented. Matter of fact.
Also i would guess you are lighting more surface area of powder!!
10% below max is the rule of thumb that Hogden company says.
i have a 270 wsm it needs a low charge or it bolt locks on the min in my book i had some reloader 17 the maker of it told start and max load it worked! only in that firearm ( i asked a pro he went nutso and made a video and blamed me with overloading and stuff like that ps i checked books and makers and even make of barrel too) if 3200 ft is equal a factory load i cingo it after balistics was way off the same load in 6.8 western has 2850 there nearly same rifle it odd i went for a 6mm creed more the guy had a 6.8 western there the 270 was a built nightmare( my internet emails is crap the backer for testing called on land line he why we not hear?) i got ok for one then he was off i got ok a few days later i coming to get it! ok my hunting was a mess! snow and then cold and then a call for help a hunter fell! so i got a bow and extending time still!
Good to know, thanks
How do you do subsonic loads for a 308 then?
Correct powder and a large bullet seated deeper to reduce the volume is one way. A custom piece of brass with lower interior volume is another.
Case looks like a 6.5 creedmoor ;)
obviously 800 win mag
My max load is 41.0. Minimum load is 38.0 in the manual. Your telling me to drop 10% from max load ending up at 36.9? Thats more than 1 grain under the minimum load in my manual
Most reloading manuals recommend starting 10% below max load. Depending on the cartridges or powder being used that 10% can drop below the minimum charge listed. If that’s the case, I would start off closer to the minimum charge and work my way up while looking for any pressure signs. Additionally I find that starting somewhere in the middle usually works for a good starting point.
Some loads have a much smaller range too, so the 10% rule isn’t universal. Look in the manual and you’ll see lots of examples where one powder can be used across the whole table and another is only listed for 2 or 3 weights
Is there any way to combat this?
Jake Birkmaier don’t go below minimum charges listed in the reloading manuals. That’s the best thing
Vaughn Precision I mean for instance if you wanted to make a sub sonic .243 load (which would be silly buy whatever) or a load that wouldn’t burn out your barrel or give as much kick is there any way to go below the minimum value and still be safe? Maybe like a filler that mixes with the powder?
Jake Birkmaier the only thing you can do is use a powder called Trail Boss. It’s based on volume but is famous for low recoil
Yes there is. Shotgun reloaders frequently do this for skeet and trap shooting. Any "filler" can assist with this and many use cotton balls but you have to be careful with that as variations in amount of filler can alter pressures also. Check into it and you will find people reloading with fillers to prevent this problem. Reloading has and will always be dangerous so do your own due diligence regarding this.
@@vaughnprecision what if you packed the empty area with a foam or cotton, to keep all the power pressed firmly against the wall, so that way even if your shooting down into a drain whole, or just straight down from a hight. You would have primer igniting to empty space.
I guarantee that you are one of those people who always say start 10 percent and work up.. you really didn’t tell us anything. And if your theory is correct how does shooting lead with pistol powder work… not at all being smart.
God bless you and good luck
Could have looked ar fortunecookie45lc video on here 2 yrs before your made yours.
I did
I watched Fortunecookie, then this.
I like both, but didn't pick up on the arc flash moving the bullet into the lands which plugged the bbl until watching this. Thanks both of you guys for the explanation.