AR15 Barrel Bedding: The Video That Revolutionized My Approach
HTML-код
- Опубликовано: 9 июл 2024
- How I think about AR15 barrel bedding really changes at the end of this video. I know it is a long video and I don't blame you for skipping ahead. But I think it is worth it if you take the time to watch. It all started this last winter when I watched an episode of Brownell's Smyth Busters. They were talking about AR15 barrel bedding and if it is worth it or not and if it is even necessary. Like most of us, I just assumed that it was because I've seen people do it on RUclips and talk about how great it is. But is it really needed now with modern manufacturing processes? Can AR15 barrel bedding really make a poor performing rifle shoot better? Are we even asking the right questions at this point? After you watch this, I encourage you to watch the Smyth Busters episode in question. Here's the link: • Smyth Busters: Should ...
Some of the tools I use I put part #s and where to get.
For your convenience:
**Time Stamps**
00:00 Intro
00:52 How to Lap the AR15 receiver face
02:54 My AR15 Barrel Bedding methodology explained and install
08:53 Target Comparison: Un-bedded, Bedded, and Bedded with a stable
rest (because I suck)
11:10 Smyth Busters: Should you bed an AR15 Barrel? My 3 takeaways
13:30 Where I change: What's good about interference fit?
14:55 THE OPINION: Should you bed the AR15 barrel?
16:03 Opinion: AR15 Receiver Lapping
16:28 Opinion: For AR15 accuracy, where you should really focus.
patreon.com/nobodytraining
Thank you for watching! 
Развлечения
Great video! I had groups around 2"" @ 100y. Tried the lapping and then compound, to no avail. Actually, shot worse. Especially, clean cold bore to hot fouled bore. Finally as u suggested, i used a 0.002" shim+compound and installed barrel (w/ heat on upper receiver). My groups are now 3/4" at 100y. Thanks so much!
That’s an awesome result! I’m very glad that you stuck with it and got it over the finish line. Well done!
According to what I've seen from long distance AR match shooters/gunsmiths, you may have lucked out by facing the full face of the upper barrel port as you did. There is a risk of removing too much because the upper face, although not completely true in matching to the barrel extension, is (by design & specs) the adequate length needed for secure mating. This is why those gunsmiths will seldom face more than 75% of the upper face, to avoid the dilemma of potentially removing enough face material so that the extension protrudes a fraction too far into the upper. Another tip is to place the shim stock across the top of the extension so the extension pin helps prevent the shim stock from trying to push past the extension lip upon insertion. The gunsmiths will often use a rubber or wood mallet to gently tap the rubber into place without the need for the addition of a fit compound. As for the never-seize, anti-seize compound, you appear to have been somewhat liberal with the application, when only a tiny amount lightly brushed on a few threads will spread and sure the purpose you seek when the nut is screwed on, torqued, loosened and then re-torqued. You're on the right track, keep chasing the long distance bullseye. Next you can go after those ultra long barrels with custom length gas ports & gas tubes.
Just FYI, for any future readers, barrel extension shims are available in case one laps too much or the upper is too short.
You're completely right on all points. A caveat I would like to add though is most upper receivers are at high spec, and someone who's experienced in lapping would likely not approach taking it out of spec. That being said it is something for newbies to watch out for. You can always measure your low point with a set of calipers or other precision measuring device to ensure you have the capability of taking a couple thou to true the face.
Using a reaction type of mounting tool, one w a “wing” that goes into the charging handle/gas tube slot in my opinion stabilizes the barrel extension and the upper receiver and during proper torquing (ie. pushing/stabilizing the barrel towards the tool) while torquing does a better job and the most realistic alignment/ mounting for the platform. Some upper tools that mimic Geisele are better due to barrel extension lock up but it also personal preference. Advise staying away from aluminum models unless build usage is not going be excessive due to over stressing the tool. Also, I believe this was stated but if not , during mounting , torque barrel w 33ms or copper anti seize and do it three times as in torquing back off nut, thread 3/4 ish of the nut and retorque and repeat for three times . From there, increase torque in 5ft lbs increments until realistic alignment and try not to exceed 65lbs( personal preference) allowed up to 80lbs G.I. Spec nut. But excessive torque “ possibly”can rreact w undesired receiver stretching creating “possibly “ a less accurate rifle. That’s most specifically w steel Gi nuts , consider barrel nut shims past if it’s needs to go past 65lbs to time correctly. Strictly one persons opinion…ps edit almost forgot , realistically doing anything of this properly w a “ reaction “ rod esque tool, the notion of snapping a alignment pin / damage receiver should truly be a misnomer as if done correctly and either issue arises, it would arise during at some point during use and personally feel I’d rather discover component failure here than when it’s actually needed. Summed up, minimal chance of damage to quality functional parts.
I used to use sleeve retainer but then I just started using BCM uppers. I can almost guarantee you that you will never need a shim for an in spec barrel extension using a BCM upper and you will most likely need a rubber mallet to get the barrel into the upper receiver. I am doing a 6MM ARC build today. I have had the barrel in the freezer overnight and once I get the received face trued I will heat up the uppers threads and with a little gentle hammering get it in place.
Was this a "blem" upper? Im wondering if their blem uppers are also thermo fit.
I am doing thermal bedding so I have to heat up bcm upper.
Similar to JP method.
It works great.
This is basically just doing the exact same thing that a thermal upper does. I don't know why people think this method is stupid or insane. Some of the most well respected barrel makers and rifle manufacturers do this or recommend doing this for maximum accuracy
Try doing your lapping vertically not horizontally. The way the tool fits in and the weight of the drill does make a difference, at least that is what I was told when I received my training.
especially that big ol M18 drill
I have faced and shimmed all of my uppers for many years, but never saw the need to bed. I agree that modern machining is great, but with so many parts mfgs out there and the nature of Frankenbuilds, you are bound to run into tolerance stacking issues between parts at some point. Another unmentioned, but huge advantage of shimming the barrel is to keep the barrel in line with the upper. Keeping scope/optic windage adjustments as close to center as possible will absolutely help in the accuracy department...especially at longer ranges.
That’s a good point. I looked at shimming only from the point of keeping the bore inline with the bcg. Thanks for sharing!
You really need to do 10 shot groups for accuracy testing
Great VDO - I think your conclusions at the end were 100%. I totally agree with your caveat because things slip by on Mondays after a good weekend, irrespective of manufacturer. I still think the guys that have already said this below and Brownells recommending a thermal fit is sound advice if you’re going to chase the MOA Dragon. I think your theory is plausible but may require some luck, i.e., increasing diameter with shim stock followed by thermal fitting. Buy once, cry once applies on this barrel concentricity endeavor. The odds are in your favor with a proven manufacturer that incorporates thermal/interference fitting.
Nice video!!!
I have to admit, if I were going to do a RUclips channel this would be the name.
As to bedding AR-15 barrels, I think you're on the right track. The builder must check part fit prior to final assembly.
As far as accuracy, I put a muzzle break on my rifle. I have shot a 1" group @ 100yrds with it.
Good stuff sir. Thanks for the work!!
Much appreciated and as always, thank you for putting up with me!
You suggest using perpendicular instead of concentric. To explain in the machinist world those words mean two completely different things. Concentricity is referring to the fact that they are perfectly on the same axis. Or at least as close to that as is possible perpendicular would mean they are 90° offset for each other. Concentricity is extremely important when you have two separate parts that are machined at different times. Two cuts will never be the same so you have to true items to each other. Therefore making them concentric there's a lot of different processes and some are more accurate than others put in general concentricity and perpendicular are two completely different things. Hope this helps
Great video! I had done mine a couple of years ago. I used a 1 thousandths shim and it stopped halfway and wanted to crinkle. I had to heat upper to get it to finish sliding in. I had already seen the video from the company that heats to mate their’s up. Thanks again!
The facing I can agree with but bedding the barrel with the shim I am not so sure and why would you use retaining compound when the barrel nut hold the barrel in place. OK when you trim some of the shim off and it is not at least 355° around the barrel allowing 5° for the for the pin ... so when you trim 2/5 th of the shim off and force the barrel in the receiver you are forcing the barrel off center as it is being forced up toward the pin where there is no shim! Just my $.02
If you just put a piece of “ shim”‘anywhere on the barrel extension, you are NOT centering the barrel. In order to fully “ center” the barrel, you would have to wrap the shim material fully around the barrel extension, cutting out for the locating pin. The use of any type of “ locktite” is a waste of time. It’s called a thread locker for a reason, it fills in around the threads of the screw ( bolt) when it’s tightened down. It’s not meant to fill gaps.
The Loctite used isn't regular thread locker, the brand sells other types, and if you hear in the video he is using 638 which is a slip fit retaining compound, which expands to lock In the barrel, up to about 0.010" which can be plenty enough to do the job with the added shim thickness.
there are FOUR things you can do to improve the accuracy of your rifle , and the Size your groups..... :
1 - make SURE the barrel Crown is PERFECT
2 - buy a GOOD barrel to BEGIN WITH
3 - put a GOOD trigger in it
4 - learn to squeeze the trigger
if you, (and your rifle), are capable of shooting 1/2 MOA at 100 yds, THEN you MIGHT see an improvement by "Bedding" if you can't, you need to fix one or all four of the above......have fun.....OnWard..........
Well, since you ran the shim only half way, you would just need to run it all the way around, then thermal fit it....
I have lapped, shimmed, and bedded LOTS of uppers and had great results. I think a lot of it has to do with the quality of the barrel you are starting out with.
Also, the fit of the bolt to the extension. Seems like the tighter the fit, (but still within specs) the more accurate it is. This is souly my opinion and personal experience.
I do agree. After a while, I come back to this and mess with different bolts. I could tell you the results, but I think you already know!
Interesting video. You touched on a subject that is becoming way more apparent in the firearms industry, which is very poor quality control! IF... the manufacturers ALL used the same dimensions as dictated in the TDP for the AR platform for the upper receiver and the barrel manufacturers did the same for the barrel extensions there would be no need to "bed" the barrel to the receiver........and regarding nearly EVERY component of the AR, which finding quality spec'd and good QC components is becoming a roll of the dice.
To my knowledge BCM, JP and SOLGW (ZEV / MEGA) are currently the only companies offering the thermal fit upper receivers.
As a suggestion to the DIY people, invest in pin gauges and good calipers to actually measure the parts you are intending to use in your build, especially if you intend to build multiple rifles. Yes they can be expensive to purchase, but at least you'll know what you're dealing with!
For the 1 or 2 rifle builder.......just purchase one of the above mentioned uppers and go with that.
Finally........the off the rack M4 / M16s standard accuracy is typically 3 to 5 MOA at 100 yards. So if your AR is shooting less than 1 MOA consistently you have nothing to worry about not to mention the average shooter isn't capable of much better accuracy than that.
I do like the idea of shimming and thermal fitting, but the important thing to remember is to not over heat the upper receiver!
My wilson combat barrel would drop right into my mega upper. I had to shim it. Barrel and shim in the freezer and heated the upper. Rock solid after that.
I dont think it matters whether you bed it or not, the accuracy comes from the chamber and the barrel, this has 0 to do with accuracy
This is an operation which is perceived to improve accuracy but it is not at all proven. What’s important is a match grade barrel extension fitted to match grade barrel. I know this as an American High Power Rifleman in Long-Range Award Winner. Bottom- line is match condition your AR as the USAMU does, nothing more and nothing less. Their comprehensive research and development has identified everything important to getting the best performance from an AR, about .25 MOA at a 100 yards. My AR delivers .50 MOA from irons in prone sling supported position which is good enough to produce 500 x 50 X scores from knowledgeable and skilled shooters. My best is 482 x 14 from irons.
Terms are being mixed up here. Concentricity is not the same or interchangeable with perpendicular. When you face your receiver you are making sure the surface is perpendicular to the bore not concentric to it.
Great video. I want to get more into building like this.
It’s a ton of fun!
It is. And the feeling of doing it yourself. Amazing job.
Great video!!!
I don't know but I am pretty sure I saw that shim crinkle between the receiver face and barrel extension at 7:22 on the video. I have two builds under my belt now. With both, I lapped the receiver face and bedded with Locktite 638. I am very happy with the accuracy of both.
Here is the issue I have with inference fitting. When you heat the receiver, you are likely heating unevenly. As a result you get uneven expansion and possibly a slightly off centered barrel as it cools unevenly. The best is when the barrel and receiver fit nice and snug and the matting surfaces are flat and even. So I'm OK with lapping but it must be done evenly.
Been saying this for years. Buy a quality barrel, bcg, upper, and some quality glass. Good trigger will take the meathead out of the equation some.
What if...the upper is in the vice block vertical, the barrel nut is 'just' touching and the BCG installed, removed, installed a couple times to establish 'centerline' alignment (concentric) before torquing the barrel nut? With a faced receiver (perpendicular) and an aligned barrel (concentric) I don't see the need for bedding (My humble opinion, your mileage may vary.).
You don't understand if your Barrel is slightly off to the side you just adjust your scope to compensate......
I respectfully recommend you look into bolt action rifle blueprinting and the reasoning behind it. And then come back and think about what and why I’m doing what I’m doing.
I think your over thinking the whole interference fit/Thermal fit.. It's just because it's a nice tight fit.. Also most of your AR15 accuracy comes from #1, the barrel, a quality barrel totally changes the way you look at a AR15 for accuracy. After that, #2, the ammunition, you have to shoot quality ammo for consistency.. #3 a good AR15 trigger like the triggertech diamond, makes a world of difference.. I dont bed my rifles, the last 20" AR I built with a well known barrel maker is shooting in the .2s and .3s at 100 yards. This is of course off of sand bags with a large variable power optic and quality ammunition... I also do recommend a thermal fit upper, at least that's the way I roll with mine.. Good luck with your accuracy quest bud...
Enjoyed your video. New subscriber!
I appreciate that. Welcome to the channel!
I have been scouring the interwebs and forums for more information on this. I am currently building a MK12 mod 1 clone. My issue that I am currently having is the Douglas 18” 1/7 twist barrel is very sloppy in the colt keyhole upper. Way sloppier then what you experienced making this video. I came to the conclusion that I would use stainless .001 shim material in conjunction with locktite 640 to bed the action. I do believe the smiths at Crane bedded the barrels to the receivers on the Mk12 mod 0s. I may have to do a before and after as well. See if there is a notable gain in accuracy.
I really wish I could afford to take 10 barrels that are exactly the same and test everyone of them. Bedded/unbedded, matched bolts, interference fit, etc. really drill down to what truly matters. But it will have to wait till I win powerball.
Please report back with what you discover!
@@nobodytraining I have built uppers using BCM and they have all been thermal fit and they are solid. I have juggled with the idea of just using a BCM upper but if I’m cloning. Then clone.
@red4sierra It’s a tough call. How close to clone to keep the spirit but have the performance?
@@nobodytraining I’m building a mod H inspired mk12 also using all BCM parts minus barrel and hand guard. That will be a thermal fit. See which platform shoots better if I can do my part.
Barrel bedding is a myth unless you have an upper receiver bore or barrel extension that is out of spec. In which case the manufacturer needs to replace them instead of you having to fix it yourself.
I think these are options when you have inferior quality parts, and there's that much slop that needs to be corrected. A better solution would be to invest in a quality armorer's course and learn the why's of what seperates quality from inferior products and after that once you know which companies invest in their customers and take pride in their work and care, it becomes much easier to build, pretty much all but guaranteed everything will marry together in a sympohny of awesomeness. Of course, there are no absolute guarantees when human error is ever lurking and possible, but for the most part, quality parts fit together even when made by different manufacturers because they adhere to the fundamental specifications. You greatly increase the probability of not having fitment or function issues.
Not all ar's are created equal.
You'll be passing those boxes of shims to your grandchildren.
Most likely as a Christmas present
Lol...I have unopened shims on a shelf in my garage. Ought to gift them to my son for a Christmas stocking stuffer!
I saw the same Criterion barrel video you did. Are you using criterion barrels in these tests?
Not for this. This was part of a series messing with a PSA upper. But I do have criterion barrels and they are great
I would be willing to wager that if shot 20 rounds in each condition and ammunition, you would find that it wasn’t the bedding that caused the accuracy. The barrel probably has so much more impact on accuracy than the bedding. Hornady has some fantastic videos on bullet jump and tolerances in the barrel. You have to remember that the bullet indexes on the chamber and not the upper receiver.
I use barrel grease when assembling my rifles. I have several sub-MOA gas guns with moderately priced components.
Every upper receiver I have used required lapping, just saying.
How do you hone the barrel extension. You assume the barrel rind is machined near perfectly true.
I’ve never found a tool to do so. If you have access, you could set it up on a lathe and see how true it is…after you pull the barrel extension pin. However I think we all just assume that it is probably close enough.
Smithbusters..."do we possibly create the reason for someone to buy something"...maybe!!!
Maybe you talked about this and I missed it. If you bed your barrel, does it make it harder to replace?
It’s not difficult. I use some heat and a wood dowel and tap it out
Probably less work to just buy a BCM upper. Super tight around the barrel extension, usually requires heating the upper to seat the barrel extension. The 4 i have showed trueing was not necessary....maybe I was just lucky
John Holliger , owner W.O.A. , Joe Carlos , American Gunsmith also here on this platform .
What do you mean by this statement???? That there here watching or ???????? Thank you.
When you torque the barrel nut to the upper receiver, the receiver will constrict around the barrel extension..When you get to 55 to 65 pounds of torque, the constriction stops.. Unless the fit between the upper to barrel extension is excessive, bedding is pointless..
I don't doubt your point on torque and constriction. It would be interesting to know, and I'm not sure how we'd go about it, what the constriction rate (in .001") vs. torque value. Barrel nut torque has a wide envelope as does extension to receiver fit with so many manufacturers. So what would define as a loose fit? I have yet to find anything on that. I did find an old video series of Joe Carlos and he shims and loctites all of his barrels with improvement in accuracy. It's an interesting video series and worth the watch to find some of those useful nuggets of info. To me, unless the barrel barely slips in or is a thermal fit, it makes sense to bed. Takes the guess work out and you eliminate the over torque or under torque issue, which can affect POI and/or barrel harmonics. Speaking of barrel harmonics, I read a long time ago, that some will torque the barrel nut in 5lb increments, starting at 30, until the desired grouping is achieved. But I don't recall if that was a bedded barrel or what.
BTW- Love the shepherd
@@nobodytraining The TDP upper receiver barrel extension bore is suppose to be 1.00" to 1.06", but many receivers today are under the 1.00 minimum..Bedding a barrel with Green loctite/shims won't hurt anything, but I don't bother if the fit is snug..Barrel extensions are not all the same diameter either.. I use pin gauges to measured the receiver's barrel constriction with different torque settings..With the wide variety of uppers I have (including BCM) they were all with in the 55 to to 65 ft pounds torque range before the constriction stopped..The another area I have found to have effect on accuracy with the upper is the amount of play (slop) the rear of the carrier has within the upper..The more slop in this area, the less accuracy I have seen occur..Keeping the bolt in line to the chamber/bore does effect accuracy..If you have access to a sample lot of AR rifles, you can measure the different amount of rear carrier slop AR rifles can have..I had one brand new retro upper that was so far out of spec, I sent it back..Accuracy gurus will use or claim all sorts of voodoo, but this is what makes the search for accuracy fun..According to Colt, the variance between 35 to 80 ft pounds of torque has no consequence..Barrel nut material can also determines the barrel nut torque..When you find the perfect combination, let us know :)..Have a good day..
A couple things from my experience with barrel bedding. The extension lapping will true the fit to the shoulder ring on the barrel and that will assure alignment of the bore to the receiver and the bolt face. But that is a single point of contact (in the linear sense) and the shim/Loctite 638 will extend that point of contact all the way through the barrel extension for a much more sturdy and durable fit. Where accuracy is concerned, there are more factors at play than just the barrel to extension fit. In your case, you're using factory ammunition which is mass production and a "one size fits all" approach to shooting and guarantees larger groups to begin with. Barrel quality and harmonics will dictate accuracy and if you're going to use factory ammo, I suggest you try other brands of factory ammo until you find one that your barrel likes. Hand loading is infinitely better than factory ammo because when hand loading you can tailor your ammunition to your rifle. I took a friend's AR-15 that shot patterns, not groups, of six to eight inches at a hundred yards and replaced his barrel with one of my used FN barrels, and through lapping, bedding, and creating a custom load for it, got that rifle shooting under 1/2" groups at that same 100 yards. So keep in mind that barrel bedding is only one aspect of improving accuracy... not the only one.
Does shimming increase odds of misaligning the feedramps?
No. The index pin takes care of that
Ive had better luck using Molybdenum grease as a bedding compound around my stainless shims.
It helps stick the shim to the barrel extension, and helps the shim glide more freely into the upper receiver without binding.
It won't function as a retaining compound, but if your shims are thick enough, you shouldn't need it. Especially with the pressure from your barrel nut holding the barrel into the upper.
Well what this shows beyond a doubt is your gun is more accurate then you are, and that is the way it is going to be for most shooters.
My thoughts exactly.
White Oak Armament barrel fitted with a competition barrel extension . As far as upper receivers , if ya go to a quality machine shop around the end of a lunch break you'll probably see a few employees outside smoking or talking , approach them and ask them how to find out if your receiver is what it should be . Most of the time they will tell you how to word to the desk clerk what you want checked. Sometime a foreman or an owner will ask , do ya have the barrel and barrel nut with ya , and take you out back and in 10-15 minutes you have your answer and maybe a new shooting buddy and a new place to shoot. Getting a coffee one day a couple guys I had been talking with a few months each morning yelled over to a guy at the register he came over and 10 minutes later I had directions and a key to a sandpit where I can shoot all year , except during hunting season ! Talking to people in the real world sometimes works out really good .
I've only built two ARs, and I haven't had to lap or bed either one. But I'm also spending top dollar on quality parts.
Spot on. Don't buy discount stuff and expect precision. I've built two 15s and one 10 and purchased the best quality parts. Didn't lap the receiver nor bed in the barrel. No issues with accuracy, beyond my personal ability.
EVERY upper receiver should be thermal fit. It's 2024 for God's sake....and the AR is THE most common firearm platform (maybe except the Glock) and we still have to deal with this nonsense?
I can only name about 5-6 companies that offer thermal uppers (off the top of my head) SOLGW, VLTOR Mur, JP, Zev, BCM....I'm sure there are others, but EVERY company should be offering thermal uppers!
I would pay $50 more to have perfectly lapped, thermal upper receiver.
The tightest sub moa groups i ever shot at 100 and 200 yards was with a PSA 11.5" i took the barrel off and to my suprise it was a super loose sloppy fit. I still prefer thermal fitted uppers like bcm.
I hate to burst your bubble, I’ve never bedded, only used AeroShell 66 on barrel extension, and nut threads. Sorry it’s a waste of time, my two builds shoot sub sub moa with hand loads.
None of my AR's have been bedded and all shoot sub moa with the right ammo .
This is a voodoo process at best. Feel goods attempt to take a semi or in some cases full auto rifle and make it into some sort of DMR for all the encounters out past 100 yards. Its purpose is mainly getting hot lead down range at a rapid pace. Accuracy is a non issue with this type of battle equipment.
So basically with the targets at the end u showed that it makes no sense to bed your barrel.
So the hard thing about my style of videos is that I tend to do series. Is bedding pointless? No. My opinion is that there are other things that are more important and bedding is the last little bit that helps.
Comment ed❤❤❤❤❤❤❤❤❤❤
What for.....
The runout on the drill is pretty terrible.
If we were cutting a hole I’d 100% agree with you. Even though the lapping tool isn’t a precision tool it’s pretty good at lapping. That’s why a steady pressure is necessary as you can imagine!
@@nobodytraining I'm thinking with a lot of runout, the lapping tool is not lapping completely completely flat. I imagine it's now wavy around the circumference.
It is a hand tool and completely completely is as you say not possible. If there is any waviness then it’s so minute that’s it’s inconsequential. The goal is to get the face squared off so it’s perpendicular to the bore…as much as is possible with a hand tool. I’ve had good success with the lapping tool over the years.
If it was truly wavy we’d see that on the receiver face the first time it was cleaned up. It would show choppy anodizing all the way around instead of what we did see. The tool does move on the X and Y axis. Impossible to keep it from doing so. Movement on the Z axis is minimal.
What I always do is put it on my granite inspection table and lay the face of the upper flat and see visually if I can see any imperfections before I lap. If there is nothing I can see visually then I don't lap the upper.
That is on my list of things to eventually get.
Fk headspace 😂
Agreed!!
Never have “ bedded” a barrel😂 no gun manufacturer has ever bedded a barrel😂 it’s just another silly AR myth.
ruclips.net/video/TvWYzCGEuxo/видео.htmlsi=E1nYPIMO5qVdKqCb
Here is a video of Criterion installing a barrel AND using green loctite. Which by the way, loctite makes all kinds of cool products, like thread lockers, but they also make SLEEVE RETAINING COMPOUNDS like Loctite 620 and 638. All designed to lock 2 cylindrical components together…like a barrel extension and receiver. You may also want to find the article retired Master Sargent Joe Carlos wrote for American Gunsmith magazine about a decade ago about shiming and loctiting. He builds precision ARs by the way. And he’s forgotten more about this subject than what you and I know about combined.
As for no Rifle companies “bedding” their rifles…well most will not because that costs time and doesn’t really effect their bottom line for the type of consumer they are targeting. After all, it’s good enough. However, the higher end companies like JP and BCM, for example, do a better form of bedding. Bedding, if we all remember class, is a way to lock the barrel and receiver together so there is no movement and that makes the platform more consistent. Movement makes things inconsistent so best to immobilize as many things as possible. Well BCM, JP and some others do thermal fitting and that is by far the superior method of “bedding” a barrel because it keeps everything as true as possible. Shims, as you pointed out may not go all the way around, which at the end I believe I pointed out it would be best to use shims and thermal together but that’s another story. The way I did it in the video wasn’t perfect yet it was better than it was without since it brought the barrel closer to center of the axis of the receiver/BCG. But it is probably off by .0005 since I didn’t go all the way around. Which you pointed out as my sin. My bad
If you just want to dismiss this as a silly ar myth, that’s up to you. It matters not to me. Ultimately, whatever you do is up to you. As for me, I’ll keep my intellectual curiosity going and test things out to find better ways of doing things.
There is absolutely zero reason to do this.
I agree. If the barrel nut is properly tightened and there is zero play. The few thousandths won't matter and will be compensated by the scope or sights. The flat face of the nut and barrel will put even pressure and should deform the aluminum to the correct tolerances.
The high spots just proved there was a reason
This is very unnecessary.
Faxon match grade barrels. No need for any of that as they are an exact fit.