223 Rem - AR barrel heat test

[@Ruteger100]

Man I miss this channel more than any other. Please come back.

[@inspiredartphotos]

I have about 12 years of competitive shooting experience. 2 years shooting High Power, 4 years in F-Class and 6 in Rimfire Benchrest. These disciplines require a lot of wind awareness. I just binged watched your Blackhills 77 gr. Cloning series. Excellent videos. I have shot both White Oak and Rock Rivers. Now my point. I can see from the background bushes and tree limbs there is a wind cycle going on. Some of the groups were spoiled by wind switches and a very different condition. That typically shows up as horizontal in the groups. You have some groups that had almost no vertical in the groups but had mostly a horizontal component. I now do load development over very high quality wind flags. If you shoot in the same condition and do not shoot when there is a switch or bad condition it can really improve a rifle’s grouping. I was blessed by my friend and shooting partner who has been a two time ARA champion and RBA champion. He is a Hall of Fame member. 223 projectiles can be really influenced by wind. I thought I was a wind reading God coming from F-Class to Rimfire Benchrest. It was more than humbling. At least I was blessed with somebody who could teach me. He never shoots without wind flags… Knowing when to wait out a bad condition is an essential skill. Tune for vertical and try to shoot in the same wind condition.

[@DummyRound]

That loop of the shot marker was pretty awesome to watch the impacts move around the target. Thanks for Episode 0 of your new series, Mr.Bench 👍🇺🇸

[@maxwellfairfield888]

This kind of endless testing/theory is exactly what I wanna see. Love this content

[@corycarlson8712]

I am actually impressed with how they stood up to the heat. I expected them to shift poi and loose accuracy much faster. This is great information to have. Thanks for all of the videos!

[@Warmachinellc15]

Hey Johnny, I documented a significant increases in precision when bedding the barrel with SS shim stock wrapped around the extension AND green loctite ala Joe Carlos of the Army Marksman Unit fame. About a 30% decrease in group size. Also I had to do it twice. The first time some of the shim bunched up between the extension flange and the receiver face. I also had an Aero Enhanced receiver so I didn't see it. I had months of all sorts of weird groups and poi shifts after the initial documented improvements. I would shoot a great 5 shot group, then halfway through the next one I would see about a 5 MOA shift. I thought the scope was the issue. After I pulled the barrel and re-bedded it. Boom! No more shifts of any kind and amazing groups. I'm still doing load development but so far I'm at about 0.5-0.6 MOA (Aero M5E1 in .308). Before I fixed it, the weird shifting was exacerbated by heat. It would shoot great then the wheels would fall off somewhere after 5-10rds. As the barrel got hot. Since the fix there's been nothing of the kind. ETA: I also lapped the receiver face with a lapping tool I modified to work kn the Aero Enhanced M5E1 receiver. I know you are shooting an AR15 but if you want to borrow it for the M5E1 just let me know. It should still work on the non- enhanced receivers. I'm in KY too.

[@Physics072]

I have a Aero Enhanced on a 24" bull 223. I just used the grease and 55 pounds of torque. Getting 1/2" groups. Did you put locktite on the extension or threads? Also what does the shim do since Aeros don't need a shim to line up the gas tube.

[@Warmachinellc15]

@@Physics072 Hi Bob, you still use grease on the threads. The shim gets wrapped around the extension essentially making it 0.001"-0.003" larger on the outside diameter (depending on the shim thickness). You want the extension with the shim to not go in the receiver at room temp but slide in when the receiver is heated up with a torch, making a thermal fit. Before putting the barrel in the hot receiver, you apply green Loctite around the shim/extension. Wipe off any excess after seating in the receiver, you do not want it on the threads. Then you install the barrel nut with grease as usual. The shim will not affect the timing of the nut or the gas tube. The Loctite will slightly expand and lock in the extension when it dries. The thermal fit, combined with loctite will produce a very rigid joint connecting the barrel to the receiver. This is all very easily reversed with heat as well. I'm almost finished with load development and am currently shooting 0.27 MOA with the .308 with just a standard 18.6" 4150 Faxon GUNNER barrel.

[@stevenallen2530]

Great content, I'm new to reloading and I have been watching many of your old videos and find them very informative. Thanks, looking forward to what's next.

[@otetechie]

I love the 5.56 SPR videos. It’s what brought me to the Channel and got my started reloading. I finally picked up a WOA SPR on speak like a pirate day. It’ll be fun to see how it compares to my old HBAR.

[@greasegun1313]

My Sprrrrr barrel showed up this week 👍

[@joethearcticfox]

I would love to see the results of torque tuning. I don't think I've ever seen a good test on the subject, just anecdotes and opinions.

[@aaron.from.winchester6744]

I agree. I think it does make a difference, IMO. I know it made a difference with my 6mm ARC build but it is a much heavier bbl.

[@NineteenEighty-Four]

AMU found 60ft/lbs to be optimal for across the course.

[@georgecolee7663]

kzbin.info/www/bejne/fpi7mIOAj6l5j6c. Wish granted

[@joealtimus3201]

I love your videos.....I have learned ALOT from them. And I'm still learning. Thank you for all the knowledge you have shared with us.

[@jeffallen3382]

The fast forward loop of the shot marker was very interesting.

[@NelsonZAPTM]

hey JRB, jam an ear plug into the upper/lower hinge from the inside as you close the halves, use a long skinny sharp knife through the mag well to trim excess. stops U/L wobble and totally non permanent. Cheers from NZ, I miss my AR.

[@Cocaine_Spaceship]

I had a white oak barrel I put into a aero upper receiver, the fit was sloppy. I was using a geissele mk16 handguard. It shot about 3” groups with several different hand loads. I pulled the barrel and thermal fit it into a bcm upper receiver. Now it’s the most accurate rifle I own. Never thought the upper would have that big of impact. Both were torqued to 45ft pounds.

[@robertpettus6037]

Johnny, I've had great success with using stainless steel sheet stock to bed my barrels in uppers that have a loose fit because ive found the thread locker beddings to be a pain to remove and it didnt seem to last very long. Once the receiver face has been trued, the steel sheet stock trimmed, and wrapped around barrel extension with no overlap, I've been able to not only tighten groups but alleviate heat shift as well. Hope this helps, I bought a variety of sheet stock on Amazon.

[@BG-gr7fh]

Thanks for your attention to detail and execution, wealth of knowledge on this channel

[@russstockton3784]

I have a 20" nitrided 223 wilde barrel (can't remember the brand), and it shoots like 1,25 moa with just about every load I run through it. When it heats up the poi moves down and to the right , but it hasn't suffered the groups opening up at all. I don't think I ever got it super hot, but that's my experience. Great job brother!

[@Keith-mk6yt]

I have found that the repackaged or bullets labeled "2nd" will have varying weights. I usually sort mine if they are going to be used for shooting groups vs plinking. The weight variation may account for the fliers or at least you eliminate a variable.

[@KBell119]

I purchase factory seconds for plinking ammo sometimes, and have actually sorted them by weight to a tenth of a grain to test, and it didn't make a difference.

[@gradystegall4911]

I have found that the factory 2nds also have different base to ogive measurements. I have some Sierra 77 grainers with as much as .020" difference. This will affect the actual seating depth in relation to the lands.

[@JinkxSoldga]

@@KBell119 To echo your experience, Eric Cortina says the same thing. Varying weights make zero difference as well as sorting. Many other high skilled shooters say the same thing.

[@ImageThisPhoto]

Being in Orygun, I buy lots of Nosler 2nds. I do weigh-sort them know and my groups improved a lot. Ive seen deviations up to .008

[@briancowan4318]

First, you are well within 'Minute of Man'! As for tightening the groups, you definitely need a device on the end of that barrel, whither it's a suppressor, comp, brake, something. Second, looking forward to the rest of this series. Third, if you need to ditch that 'peanut butter' colored upper, I'll find a home for it.

[@nineteendelta770]

The thermal expansion of aluminum is much larger than steel but also the modulus of elasticity of metal is reduced with heat and most barrels have stress that warps the barrel with changing temperatures. In short, you have multiple factors that change the accuracy of an upper with higher temperatures.

[@garyharms8466]

I have found that lapping the face of the receiver improves accuracy and group shifting as the gun heats up.

[@trigerfingers1911]

Interesting results….glad to see another fine video from jrb , thanks!

[@vomitingwithungodlyaccurac3218]

Intriguing. I'm excited for this new series.

[@hochhaul]

I use BCM uppers because the pocket for the barrel extension is usually tight enough that the barrel has to be cold and the upper needs to be heated with a torch. I also do what Criterion barrels recommends and put loctite 680 on the barrel extension before mating the two. there are youtube videos by a guy that worked at Colt on their match grade stuff that also has tips for accurizing AR's (particularly barrel nut torque, which he gives a very specific torque to aim for).

[@coreystock5361]

I bedded my barrel to the upper and noticed a change. I was surprised. It really did help the accuracy.

[@Gunner-73]

That may be the best that barrel will do. Bore scoping the chamber may reveal some flaw or buggared barrel crown or even missing lands. Bear creek and Aero both produce a pretty good barrel. That barrel does seem to be one of their barrels, both would warrantee the barrel.

[@OddBallPerformance]

Loctite retaining compound does help with accurizing but it has limitations. In an application where the temps will climb beyond 450 degrees F. the retaining compound will begin to soften and release. Not an issue for a sport gun that see's a few shots at a time at the range but under "rapid fire" scenarios that temperature can potentially be reached and the bond goes out the window.

[@marctrossbach6560]

Look at Discreet Ballistics' pop stop. I use it and CO2 to cool my barrel. It massively reduces temperatures, and found that it also lowered my S.D. and E.S. . Essentially it is a way to make your cold bore shot repeatable

[@NSghostoif5]

Umbtech here, thank you for a new vid and had fun yesterday on your livestream.

[@theoutdoordog6946]

Suppressors do tend to tighten up groups, but they also move the POI. The best thing to do would be to get a lapping tool an square up the upper receiver before installing the barrel.

[@stephendye4602]

True the upper receiver face it helps

[@hawaiiangunner]

I've had great hot barrel testing with 77 grain Sierra match Kings with 24 or 25 grains varget. I can't remember if it was 24 or 25 grains whatever was in Black Hills blue box. I pulled the head and weighed the powder charge and used that same powder charge. Of course I worked up to that following safe procedures. I was not using 50 round groups. But I was shooting rounds 20 and shooting fast. JP Enterprise CTR 02 rifle.

[@zinfendal0]

To bed I lap the upper. Wrap 1mil shim stock on the barrel nut with a small gap in the shim stock around the pin. Install a small rubber band to hold the shim. Put the whole barrel and shim in my freezer overnight. Prior to inserting I heat the thread ends of the lower with a torch. Once good and warm. (NOT RED HOT) while the upper is hot quickly remove the rubber band and quickly insert barrel. Once all room temp it is tight. To remove heat with torch and tap out with wood dowel. No lock tite clean up to change barrel.

[@upnorthreloading2214]

I watched this about five times in a row, absorbing all that I can. More to comment later.

[@mikesauer7775]

I had a chrome moly match barrel with .002+ slop with upper receiver. I rubber banded perfect layer of alum foil and heated upper receiver to +.004 and shrunk fit bonded them. The 1"+ fliers turned to .7's. All I got

[@nk-dw2hm]

Chro-moly is different than chrome lined

[@MichaelBrown-um8qc]

so many ars are like this . really makes you want to waste the money & own one . can't wait to see what you dig up . for now .I'll sit quietly & watch .👀👍

[@lienl448]

Different powders could change harmonics. Would certainly like to see the tuner.

[@DanielBoone337]

I've got to the point if I build a rifle where I picked everything on the gun and set it up the way I wanted from the start I bed the barrel and true up the receiver. I haven't noticed a huge difference but I figure it can't hurt anything. I think they make shims that go around the barrel extention to take up that space so you're not having to use that loctite compound but Ive never looked into that. All that being said if you're buying a good barrel that's been properly stress relieved barrel heat doesn't effect things all that much and stress relieving barrels is becoming more of a standard thing across the board these days... at least that's my understanding. Great video as always keepem coming brother!!!

[@NineteenEighty-Four]

What space are you talking about?

[@DanielBoone337]

@@NineteenEighty-Four between the barrel extension and the inside of the receiver... sometimes that fit can be a little loose but if you coat the extention with loctite 620 it expands taking up all that dead space and making a much more solid of a fit up. You could also buy a receiver that you have to thermal fit the barrel that's a really good option as well... I still used the loctite 620 on my BCM receiver and my guess is that will never come apart again without breaking something.

[@NineteenEighty-Four]

@@DanielBoone337 Not necessary. The barrel nut under torque squeezes the threaded section of the upper receiver around the barrel extension. I've tried all this stuff over the years and most of it has become superstition. Free float a great barrel, not too much tension at the muzzle, and properly match a bolt to the BE is the key to precision AR's (of course work up a decent load). Everything else has vastly diminished returns.

[@davidunderwood3605]

Good video. As far as combat accuracy you really couldn't ask for better. And barrel heat being questioned then same ammunition/upper with controlled cooling time and 2,3,4 and 5 shot rapid strings between cooling periods might give you some extra data to compare to

[@ancientrenegade9243]

If I remember correctly they square off the barrel nut threads as part of the blueprinting process. Think you can get the lapping tool from Brownells.

[@GT-ev3om]

Indian head gasket sealer or loctiting those barrels to get the max accuracy out of them and BCM has titanium barrel nuts

[@monsterk7603]

Johnny, are you still using the Bob's bulk bullets at all? Those videos are what got me hooked on your channel.

[@ImNoBSING]

In the 55gr bullet test video the hornadys did the best, but bobs are not bad either.

[@Ring3R]

You should try the Brownells AR-15 upper receiver lapping tool. It produces a much more stable mating surface between the upper receiver and barrel extension. I don't put a rifle together without using it anymore - I tested it on an older build and it shrank groups about 15% but even more importantly, seemed to completely eliminate the occasional flier. I can routinely get 1.5 inch 10-shot groups from a 14.5 pencil barrel with my handloads after using it on that gun. The difference on smaller shot-string group sizes isn't amazing, but when you do a long string of shots the lack of fliers really tightens things up. I bet you'd see more consistency in your groups when you're load testing, with the elimination of fliers.

[@ImageThisPhoto]

Consider a Noveske Barrel (chrome lined). Their reputation is built on hot barrel/combat shooting. Would love to see how those holds up compared to BCM and Aero.

[@larrycaro1333]

Thank you so much great job

[@pubgerm6454]

You can also use shim stock if you need to snug up your barrel into the receiver. Although a good receiver should be a very snug fit from the get go

[@stevenhixon5108]

Here is how I tested how barrel heat affected my accuracy: shoot a 5 shot group from a cold barrel, do a couple mag dumps with range ammo to heat up the barrel, then shoot another 5 shot group from the hot barrel. What I found with my barrel was the groups did open up, but the point of impact didn't really change.

[@heremyjogan]

The concentricity of the the receiver where the barrel mates up might have some variation. Trueing the mating surface on the receiver may help. Similar to blueprinting a bolt action rifle.

[@articjackal]

Maybe try one of your lumps on the end instead of the suppressor. Seemed like they helped when you were testing to see how the suppressor affected your groups

[@mtnshooter2487]

Yes, check barrel journal/ adapter to upper receiver fit for looseness.

[@burtlandcastor8359]

I use stainless shim stock and heat the upper to create a high interference with the upper and barrel extension. I use a mic and dial bore gauge to measure to initial clearance and then shim to a .001"-.0015" interference. The upper will need to get hot, but not over 275deg(edited) to achieve this but it's not difficult if you act fast. I cut the shim stock to have full coverage of the extension and have the split at the index pin, I also make a crescent cut for the feed ramps. Hold the shim around the barrel ext. in one hand while the upper is in the other hand being heated by a torch. Once the upper is up to temp, quickly slide the upper onto the barrel extension. If it doesn't make it in one go, you can heat the outer of the upper to get it to seat fully. I've found this is far superior to gluing a barrel in and also much better than the slight interference you get with a BCM upper. Once cooled you have an assembly that will remain tight even as the upper assembly heats with use.

[@burtlandcastor8359]

I also true the receiver face in a lathe with a fixture I made. It runs between centers and is thermal fit to the carrier race. It's a lot more accurate than a lapping tool and I have not had a single upper receiver have a true face from new - they all have been out to a degree when facing a tenth off at a time.

[@seanmtactical6069]

7075-T6 starts to lose temper at Approx 275 degrees F. Not sure I'd go that hot on the upper.

[@burtlandcastor8359]

You can go up to .002" interference if you are careful. Barrel nut torque I go for 50ft-lb with a no-time nut, with a standard nut I use 30 and go to the next tooth and shim for a max of 60.

[@burtlandcastor8359]

@@seanmtactical6069 I work in interference fitting with aluminum daily. 300deg isn't even close to where it will change the material. I regularly run alum parts to 500-550deg for fitting with zero ill effects to heat treat/temper.

[@seanmtactical6069]

@@burtlandcastor8359 Most AR gunsmiths worth their metal disagree.

[@Soravia]

Shorten the barrel and flute the front ends. It will cut down the load placed on back end of the barrel while keeping the fore end as stiff as possible. Once you put the weight and leverage od suppressor on, groups will worsen. Use a titanium light weight like Q Jumbo Shrimp to lessen the effect. For best results, heat up the barrel with suppressor on before you zero. Heat is a thing to consider vs barrel weight. Chrome lined steel will resist heat shift better, but mighty hard to get.

[@chaddfry5345]

First thought is to use Indian head gasket to bed the barrel extension in the upper. In the past I used Loctite 609, but there is a guy on KZbin (Fitty%) that makes a good argument for switching. Brownells has an AR-15 upper receiver lapping tool that is designed to square up the action, but I would go easy with it if you try it. I prefer to use it by hand instead of chucking it up in a drill. Other than buying a billet receiver and custom barrel, I don't know what else there really is to try (other than what you have already mentioned).

[@JohnnysReloadingBench]

Thanks in particular for that tip about indian head. I'll definitely look into that. I should have provided more details in the video, and I will in the next one... The BCM upper has already been squared with the tool you're talking about. The Aero has not been messed with because the tool wouldn't fit in the M4E1 receiver.

[@jeffallen3382]

@@JohnnysReloadingBench the scammer bots are responding to a lot of comments on your video here Shannon. Just thought you might like to know.

[@lzxray6781]

I'm building a 20" upper, just waiting on my BCG and dual charging handle. I've made up some loads of PPU 75 grain bthp for testing with it hoping they shoot well out of the barrel.

[@ddubd3771]

To add to the data, you could take the temp of the barrel at different stages.

[@Kycirion]

Whenever I assemble an upper, regardless of barrel length, quality, etc. I always lap the face of the upper and bed the the barrel in with loctite. Don't know that it REALLY increases accuracy, but it makes me feel warm and fuzzy. Plus, it doesn't hurt, so why not?

[@dandexinventor]

Good info to learn from, thanks JR! Also, I'm curious if your upper's faces where they contact the barrels, are they lapped true? That made a big difference with mine.

[@slinkyrobb]

First thing i check is gas block torque, and make sure there's a slight gap between gas block and barrel shoulder, then I usually torque my barrel nut as close to 30 ft pounds as possible along with lock tite the barrel to receiver, lapping the receiver may help but I doubt it does much good with the lock tite filling the gaps

[@jgoose7126]

I would like to see tests before and after you true your receiver to the barrel.

[@danwilliams1132]

What a can of worms. I look forward to this journey

[@bigwestreviews4933]

Johnny, please come back and follow up on this testing

[@DominicZelenak]

My hypothesis on the BCM upper having a POI shift is because their uppers use a "thermal fit", which means that you have to heat the upper with a heat gun to expand it to insert the barrel. Maybe the heat from the chamber and barrel is causing some built in thermal stress to crank the barrel downward.

[@NineteenEighty-Four]

Barrel nuts squeeze the upper receiver around the barrel extension regardless of pre-torque fitment.

[@DominicZelenak]

@@NineteenEighty-Four well if you look at the barrel nut and the barrel extension, the nut pulls the barrel into the receiver in the rearward direction towards the shooter. It's not compressing the receiver's threaded extension in the radial direction. If the aluminum of the receiver wants to warp, deform, or flex due to heat, the barrel nut won't prevent that. The nut will just bend with it.

[@NineteenEighty-Four]

@@DominicZelenak Under torque the nut is doing exactly as I stated. I'm sure you also do not realize that the nut is expanding mechanically. It's an equal and opposite force.

[@runningwithscissors3997]

Hey man - Lame, whhaaatt?! You just shot the star out and won a state fair prize! Enjoy the stuffed bear - Ha! Seriously though - enjoy the content!

[@densamme1752]

I wonder if you have a inconsistent cooling issue with the Black upper. I assume from the chart that you reloaded every 20 shoots. My assumption is that the black handguard I more open and allows a faster cooling of the barrel. Butt it is closed on the topside and therefore stops heat radiation quite a loot compared to the underside. When you reload you rifle you either lift the gun or twist it so that convection is easier that is why you get those bigger shifts after reloads. The other handguard is more closed in and seems to holding the heat equilibrium more stable. IF my theory is right then changing handguards between uppers would invert the results or wrapping the black handguard on the black upper would reduce the "lowering" of the group as heat builds up. And thx for the video as always.

[@greasegun1313]

Its a sum of the parts. The barrel fitment has a lot to do with it. Do some precision measurement of your uppers and your barrel extensions and see what the difference in dia is. If there is .001" per side or more clearance, order some stainless steel shim stock in the appropriate thickness to provide an interference fit. Then freeze the barrel, and/or warm up the upper, fit them together with the shim stock wrapped around the extension. Also use red loctite for good measure. If you never want to take it apart, use green loctite 620. If the fitment is tighter than would allow a .001" shim, just use loctite. Then repeat your tests and see if the results are evident. Other accurizing factors, use a bolt carrier with an increased dia on the rear end of the carrier for better carrier/bolt alignment. Lap the face of the upper square to the inside of the reciever. Tune the gas tube for perfect alignment with the gas key. Regardless of what you do, excessive heat in a barrel reduces accuracy as a general rule. Your groups arent terrible for 60 rapid shots. Also, use the same front rest on both tests next time as well as the same rear bag if you arent already.

[@thart909]

Git ti remember temperatures affect steel harmonics, also will slightly bend the rifling I terror for any barrels

[@jamesb3199]

Instead of one big group maybe group of 5 scoot over group of 5 and so on. Use points of aim on same plane maybe 6-10” apart. See if move or open up. Might be able to extract that from your software but I think looking at physical paper is also helpful. Could shoot 5 rounds of precise loads then say 5-20 plinkers to build heat then 5 more precise

[@joshjohnson1653]

I bed my .223 spr barrel with locktite also. Shot my best group right after! .52" I say we do it! Also lapped my upper.

[@RumblestripDotNet]

On Criterion's website they have a blog article with videos from Aug 7,2017 Criterion Barrels Releases “Accurizing AR-15” Video Series. I'd put the link but then this would end up in the SPAM section.

[@jcnikoley]

I’ve been told that as a barrel heats up excessively it will “droop”. I’m not saying I agree, but it would explain why the groups were moving downward for the BCM.

[@williambell7763]

A little personal fan for the suppressor would cut mirage by a noticeable amount. Might be worth it, just a 12/18v fan from your choice of power tool manufacturer, or something

[@williambell7763]

I also tend to go higher on the torque, and have had good results with either locktite green or thermal for uppers. Think I aim for minimum 60ft/lbs, not a rifle builder or anything but have listened to guys who shoot high power and those were some ideas that stuck out as good to me.

[@truckert9729]

I've got a rifle that will shoot half min groups with the right ammo. I shoot shotgun shells at 100 yards. Gas gun, I noticed the point of impact seems to move when it gets warm.

[@lawerncemiller6557]

Never heard of a barrel nut getting boogered up or being soft but I have heard of people that could tear up a anvil with a rubber mallet as far as accurizing a upper yes the fit between the upper and the barrel extension should be tight on mine had to heat the upper a little bit to slide the barrel into it , I've read of people using lock tight to bed the barrel in a loose fitting receiver never done it myself if it worked I'd be afraid it would be extremely hard to get back apart that would really suck especially if it didn't fix your problem of poor accuracy

[@jamesmeals1430]

Not sure what you could do other than maybe trying shims or lapping the barrel nut fit. Free floating your gas tube might help as well. Other than that I've got no clue. Good luck on the metroid grind to get sub 1:30

[@griffoutdoortv5882]

You should really try Eric cortina’s length tuning test it changed the way I load

[@bryanst.martin7134]

Can you use the data to determine time between shots? Maybe the dwell time in a hot chamber affected your results?

[@thompsonjerry3412]

Any weight on a barrel helps, where the weight is also helps, just be consistent.

[@robertjordan4755]

@Johnny's Reloading Bench ! You were shooting a bolt gun .223/5.56????

[@armedfarm3429]

It looks like you have some side wind there which will throw a shot to the side pretty easy, it doesn't take but a 15-20 mph gust to move the POI an inch. I always wondered about heat though while shooting, a good idea to test. But think you have pay attention to the wind, or it won't mean anything.

[@hairydogstail]

Check your bolt carrier shoulder bore I.D. compared to your bolt shoulder O.D...The tighter the tolerance between these two measurements, the more square the bolt face will be to the cartridge base. Then check the upper's bolt carrier channel to the bolt carrier to see how much play you have. With the bolt carrier in the upper move the back of the bolt carrier to check how much play you have between the two. The more play you have the more inconstancy you will have between the bolt face to brass case base...

[@__MAT__]

Good start.

[@paulharveu526]

Could certainly see the groups walking around.

[@solarfun2388]

I never see how often you clean it my 300 I might let go 20 or 30 rounds but my 223 50 to 100 that's why I always wondered how often you clean if you wait till your group is falling off that's to late in my opinion should check out Erik Cortina cleaning videos but love your videos used some of your data

[@nosyarg1997]

I don't know how to get in touch with you but I've been watching your videos all weekend and the last shot screws up your groups alot. The reason is when shooting a gas gun the last shot holds the bolt back so the action, recoil impulse and harmonics are completely different. I have tested this extensively and I am sure if you load a 6th round when shooting 5 round groups allowing the cycle to be exactly the same as the first 4 your last shot point of impact shift will all but go away. Wish I had your email to get this info to you. I binge watched 48hrs of your content since Friday at home sick and I am sure that is what is causing the shift.

[@daviddale3624]

If barrel heat was not an issue, no competitor would have a "heavy" barrel. The can really improves the harmonic. So does a tuner.

[@aaron.from.winchester6744]

Maybe lap the uppers? It makes sense the the BCM poi would shift lower if the bbl wasn’t square. I still think the BCM thermal fit uppers are a better option. IMO.

[@J9_j3]

i saw a guy at the range with a cloth (looks like a t-shirt) wrapped over his suppressor and he was pouring water from a bottle on it every few minutes. there was a little bi of steam, but it also was a chilly 40 degree day. he was shooting at the target at 100 yards pretty fast i could not see his target but it was paper, no gongs. i was there for a couple of hours. he was shooting when i cam an was still shooting after i was done and leaving. do a wet t-shirt test along your other test if you don't mind. it could be interesting to watch, good title for the video too, lol.

[@ron4hunting]

try shimming the barrel with stainless shim stock . make it tight enough to heat fit the barrel . it can be a pain to do but works great . what ever happened with the powder humidity test ? or is it on the back burner ?

[@alexanderm8880]

Since you mentioned barrel mirage, how would you do load testing if you don't have your own land? I'm trying to figure out a load for RMR 69gr 3GH and between the four different powders I really have to maximize my range time. I have a small fan I put next to the barrel but I still get image shifting now and then.

[@jammbbs1688]

I own an Armalite M153GN18 with a sub 200$ lbvo and feed it any ammo sofar and this thing would do sub MOA off its carry bag

[@shannonmarcantel7993]

Try a seekins precision upper where the handguard attaches to the upper receiver creating a semi monolithic upper receiver rather than attaching to the barrel nut.

[@JohnnysReloadingBench]

That's how the Aero M4E1 is setup as well

[@shannonmarcantel7993]

@@JohnnysReloadingBench that’s right, I forgot. Seekins custom shop builds sniper rifles for SOCOM in 308 and 6.5 creed. Their AR 10 platform is set up the same way.

[@Johnny-jr2lq]

Funny I literally just went through this Friday this week. I loaded up a 30 cartridges of what I thought was a good load. I proceeded to do 5 shot strings at a slow cadence. I was getting 1” groups some 3/4” groups. My last 5 shots I decided to spend up the cadence I ended up with a .5” group. Is it because the cartridge is heating in the chamber ????? Idk. But it’s really irritating to think you have a good load. Then come back with the exact same load and it shoots like crap.

[@hickoryridgefarms]

Definitely try torque tuning after 50ft lbs. and work your way up. i had this happen to me before. As long as it is a good barrel it will shoot.

[@charlesm.2756]

I might be missing the point (not the first time), but hasn't it already been well established that, as barrels heat up, groups tend to open as well? I thought that was a well known phenomenon?

[@gtroxlar8597]

I know you this is off track. Sierra 77 MK with 24.8 grains of BL-C(2) seated at COL 2.260" is shooting .400" or less out of a suppressed FNH DMR 18" with .223. Alot of folks dont like BL-C(2), BUT has become my new go to powder. I have shot it at 28F up to 108F here in Texas and have not seen any change in group size or point of impact....just food for thought.

[@seanmtactical6069]

Bed the barrel into the upper using Indian Head or Loctite 620 and retest. Don't bother bedding the gas block. I've never found it to affect accuracy.

[@jdw501]

Tru up the upper receiver lap it that helps even with hight end ar 15 among others

[@nicsu2128]

I had some POI shift through a day of shooting proven ammo. The next day went out with the same ammo and didn’t have the problem. With my last 10 rounds I decided to test a hypothesis. I gave up some of the shoulder pressure on the butt of the rifle and again POI shift. Maybe your didn’t have consistent pressure?

[@russr]

try 35 to 40 on the Barrel Nut Torque

[@SnapD24]

I've been wondering if loctite bedding is worth it, but I've never seen anyone do a before-and-after test on it. Honestly, I think using a high quality bullet will make a huge difference, but that seems like it would get expensive.

[@KBell119]

I'd say those groups are just fine for 60 round groups. If you're ever in a situation that gets your barrel hot, a heart sized group is excellent. Also a thought, does the heat cause changes in the bore of the barrel? Could there be a shift in the tension the rifling is putting on the bullet and could it expand enough to allow some gas to slip by the bullet?

[@nk-dw2hm]

If gas was starting to slip past the velocity would decrease and/or the sd's would increase. His results showed consistent velocity and SD throughout