The ar-15 platform headspaces with the bolt to barrel extension not the barrel to reciever. Now if you take off too much material you may run into feeding issues but headspace will not be affected by it.
Many are under the impression that a locking material like LocTite is needed- IT IS NOT. The torque holds the nut to the receiver. I have never, ever seen a loose barrel in the military. As an armorer I have seen thousands of overused guns. YES the facing of the upper is needed especially for long range shooting as it aligns the barrel to the upper. Facing will NOT change the headspace as the headspace is integral with the barrel. The barrel MUST fit snug to the upper and the best fit is a slip fit. We used .001 stainless shim stock wrapped around the barrel extension to fit sloppy barrels for accuracy guns as even .001 barrel shift when assembling will cause a lot of scope issues at long range. Within MIL-SPEC is a joke as it is the MAXIMUM and minimum allowable specification and still work.. FYI The shear point for a barreled upper is the last thread on the upper behind the barrel nut.
In my case though it does make a difference. I had Ruger MPR that I got rid off. After a while the barrel nut got so loose that it could have been taken off with a finger. Luckily I found that out before anything catastrophic. I say DEFINITELY blue lactite the threads. My 2 cents
I never use loctite but i do use anti-sieze on the threads because too many have come to my shop for cerakote and people do not take care of their weapons and they are rusted fast and gauled to the aluminum threads
I got the feeling he used an awful lot of loctite. I noticed two things and I'm not saying he's wrong: - he didn't use any anti-seize compound or lithium grease on barrel nut threads - most videos show tightening, then loosening of barrel nut 2-3x before final seating
@@escapedfromnewyork I believe he's just using the loctite as a bedding compound to remove the looseness and circular play in the barrel. It's not the adhesive type of loctite for securing threads. The Barrel nut is being used to apply even pressure between the barrel extension and receiver so that the loctite cures in a manner somewhat consistent with the rifles final assembly. Once the locktite cures, I imagine he could pop the barrel nut off and do the final assembly steps (anti-seize on threads, timing and seasoning/torquing the barrel nut, etc). Only kinda assuming some of this as the great UA-cam Algorithm took me down a rabbit hole of "how to's" of bedding and free floating bolt action hunting rifles before finding people using loctite 620 to bed ar15 barrel extensions.
(1) You'll not have head space issue from lapping the front of the receiver. The AR-15 head space is between the bolt and the barrel extension. Even taking a millimeter off (which is ridiculous) the head space will not change. In the extreme, the hammer will not hit square on the firing pin because the barrel is far back, but you need to take off an insane amount of material to get to that point. (2) The mating of the front of the receiver and the barrel extension's recoil ring is actually NOT SO IMPORTANT. What is more important is the clearance between the barrel extension's outer surface and the inner surface of the receiver. This is what allows the barrel to move around. It is also why clamping receivers like the LMT ARs and the SCAR -- which by design have ZERO slop in this regard when tightened -- are generally more accurate. (3) Shimming the barrel extension and packing the remaining clearance with Loctite 620 will be responsible for the overwhelming majority of the accuracy gain, finishing the front of the receiver and/or the rear of the barrel extension recoil ring is SECONDARY. It's nice to do, but not ultimately all that crucial.
@@actionjksn The SCAR will always have less inaccuracy from the barrel receiver interface than an AR because there will be zero mechanical wander of the barrel. It is a piston gun though which has less consistent harmonics than a DI gun. That said, the SCAR has a hammer forged barrel which is not all that common on ARs except those from SIGs and HKs, and I find it more accurate than ARs in general mainly because of barrel quality being higher than the average AR.
@@dwightlooiMy 6920 shoot circles around the 16S. And that’s it’s factory match and hand loads. 16S is 2 MOA at best with good tailored loads. The 6920 hovers around a minute.
Just for thoughts....Do all the work vertical. Lapping, bedding, tightening, with receiver and barrel sandwiched inside the plastic receiver block, receiver block vertical. There are much more sophisticated ways of centering your bcg,bolt,receiver,barrel if you have a machine shop and a lathe. But this is how I do it in the home armory. It's good enough for .75 MOA if everything else is working for you. BEDDING. Apply the green “expanding” Loctite (620) on the outside wall of the barrel extension for proper bedding, make sure the green coating is even around. The green stuff is not for threads yo. Still in the vertical position install barrel. Then install bcg and bolt to locking position. Tape back of bcg and receiver to give extra hold. Put some aeroshell or red and tacky inside the receiver extension nut. Wipe of any excess green stuff from the mating surface of the barrel and receiver. Tighten Receiver extension nut to 20lbs only with unit still in vertical plastic receiver block. Drop out bcg and wipe any excess green out of the inside mating surface of receiver and barrel extension. Let sit for a few hours to firm up. Remove unit from crappy plastic receiver vise block and install unit on steel barrel extension wrench, wrench mounted vertically in vise. Crank down receiver extension nut to 25/30/35/40 loosen each time. Stop at 40lbs. Most nut wrenches add a few pounds (3-8) to the torq reading anyway. Let sit vertical for a few hours. Check for any green stuff inside receiver. Test bcg/bolt fitment again, should drop in real smooth. This is assuming that you removed as little material as possible during lapping…LAPPING. If you over-lapped it then it pushes the rear of the bcg backwards in the receiver, check to make sure all components are working properly. Over lapping is not a good thing. Just a little bit is all it needs. When you see exposure of silver down there between the 6pm and 9pm position during lapping is because the lapping is typically done clockwise and horizontal with gravity pulling the tool down on the system. Horizontal lapping is how they show you on the Brownell’s video and many other videos. It’s dead wrong. Gravity is working PERPENDICULAR against the centering of the system by pulling down on the drill and the tool. And the drill operator is adding a lot of error (many thousandths) to the system by holding the drill horizontal. In the vertical you can spin the tool gently by hand and let gravity do the work. Just have a little patience. Or use a low rotation battery powered bit driver that is symmetrical with the tool and vertical, 200 grit lapping compound. A hand drill is not a symmetrical tool, especially not in the horizontal….SUMMARY. The whole idea is to keep the moving parts centered together, remove gravity as a perpendicular force during install, and don't over torq your barrel nut. It's NOT needed above 40lbs. Lastly you don't need to lap the receiver down to aluminum if not warranted. So many peeps like to grind that baby down. Just lap the hard coat until you see even removal on the hard coat, if possible. The less exposed aluminum the better. The hard coat actually helps to reinforce the aluminum extension lip during the life of the rifle. Cheers.
I’m just a hobbyists but my thought process aligned with your comment. I thought this was common knowledge until I read a lot of comments on UA-cam and forums.
Great video! I think most of the people leaving comments claiming to be "Professional gunsmiths" and slamming the use of loctite 620 are missing the point. In the video, this man is not using threadlocker on the threads. He is using cylindrical sealer to close the gap on the barrel shaft. I didn't see him put any "Thread locker" on the threads. Also, just because it's Loctite brand doesn't mean that it's threadlocker. That company makes more then just thread locker.... LOL
@Neito Kradavish considering all that hot gas is being directed to right in front of it via the gas tube, im uncertain of your assertion here. BUT i more than willing to throw my heat gun on my gun next time i do a mag dump, just out of curiosity more than anything else.
Yep it's called retaining compound and that's precisely what it's for, retaining and taking up a small gap, it's almost as strong as a weld and is a ferocious bond pretty crazy stuff
@Purple Haze the barrelled flange that meets up with the receiver is already squared up from factory. It's squared up when the barrel is formed and would be almost impossible to have that flange NOT square unless someone completely failed in the making of the barrel. The receiver is not square. You lap the receiver to get it square, which you can actually see by the lapping compound marks and then the barrel flange sets square to the receiver. The barrel nut doesn't have to be totally square because it's just compressing the two surfaces together. So there's are only two surfaces that need to be square and one (the barrel flange) already is square. The barrel nut only has to be close (which it is) for it to all pull together close. Then the retaining compound fills the gap between the barrel tube and receiver.
Kenny Wooldridge Is anybody familiar with Loctite NS 5540 High temp for Threads and Flanges? With a service temperature of 100 to 1300 degrees Fahrenheit?
I stopped watching after he said "if you take off too much you'll run into headspacing issues" this right there shows he doesnt know much about the AR15 platform
@@teddysurf Because the headspacing is set with the barrel extension at time of manufacture, the upper receiver doesnt have anything to do with headspacing.
@@teddysurf The BCG locks into the extension on the barrel which is already installed before you get it. Look into it pal, because it seems like you dont know as much as you think. This is not a bolt gun. Now have a nice day.
@@teddysurf the headspace is permanently set by the barrel extension and pinned from the manufacturer. Lapping the face of the upper, in itself could be questionable without chucking it up in a lathe and finding the true centerline. You could lap it all day and the worse you could do is mess where the barrel extension meets the feed ramps on the inside of the upper. Still would not change head space.
Ar15 headspace has zero to do with the upper receiver. You can check headspace with just a barrel (with extension) and a bolt, with no receiver even in the same room. One of the benefits of the design is that receiver variations don’t really matter, so long as the bcg and barrel are on the same axis.
You need shims for that wiggle my friend! Not a lapping job. The lapping does help but that wiggle is still there. American Gunsmith back in 2013 had a two part article written by Mr. Carlos addressing this issue. His article “Barrel Extension Diameter In The AR 15” is exactly what you need to fix that wiggle. Cheers.
Agree. I would rather use anti-seize compound, rather than loctite between the barrel and upper interface. Same reasoning for the steel nut (if it is indeed steel) to the aluminum threads. Also, I don't want to have to heat the joint to "break" the loctite if I need to strip it down.
Remember when torquing to have the tool at 90 degrees to the torque wrench other wise you will be multiplying your toque. This is taught in aviation in getting the correct torque or you will have to calculate the extra leverage and reduce it on the torque wrench.
Well done video. I am a certified AR-15 Armorer, multiple times over. I have the same lapping tool. Only two minor things I do differently. 1. I lap with upper receiver vertical. 2. I add Aeroshell 33 MS to the upper receiver barrel nut threads. Again, great video!! Thank you for taking the time and all the effort (Wifey and Daughter included, of course) to make it and then post it.
Aeroshell grease sure. However, the fact that would use locktite on a barrel extension tells me that you're not really certified. If the receiver is that loose, then you need either one of two things. One, a new upper receiver. Two, a new barrel extension; which you might as well replace the whole barrel (unless you have a lathe to set the headspace again). Two is way more work, but may provide a tighter fitment. However, 1 is the go to since it's easier to get a new upper.
I couldn't do the slop, I'd try to find a different upper before I slathered any goop on the barrel extension...For some reason billet receiver sets had slop with my Proof Research barrel, BCM uppers and Bootleg uppers were snug..
i just have to point out a few things . i build target uppers . and have done around 400 of them . first do not use the lapping tool horizontally . almost everyone on youtube does it wrong . put it in the vice vertically and it will be a more accurate lapping . do not use a drill ! or you will take off to much ! i never use loctite on barrels . get some .001 or .002 stainless steel shim stock and use it . it is cheap . wrap shim stock on barrel extension . till it is .001 over the receiver opening . than use a propane torch and heat the barrel nut thread up . 5 to 7 slow turns of the upper . do not change the color of the metal when heating . just get it to expand . and slide it on the barrel . make sure the barrel is in the vice before heating the upper . now let it cool down , and it will be ' bedded ' nice and tight and square to the upper . learned this and more from my cuz . not going to give his name . but people pay 3 to $4,000.00 for his ars and even more for his 1911's . almost all of his target uppers are built by me . and use anti seize on the barrel nut . makes it a lot eayser to get it back off if you need too .
How do you figure it doesn't affect the head space ? If you remove .005" , does that not move the barrel extension back .005" ? And wouldn't that move your headspace back .005" ? I'm confused .
Sure it moves the barrel extension back. It also moves everything else conected to the extension back ,005" Headspace is determined by the space between the bolt-face and the shoulder of the chamber, this dimension does not change. @@orionfixr7713
I might have miss spoke in regards to head space. I was trying to explain the position of the bolt in the upper receiver. I am used to working bolt actions and getting the bolts to function properly in the action and barrel. It has been my experience that If you remove to much then the Clocking of the barrel nut (depending on type) may be affected to the point you may need shims to correct.
@@HarmJW77 Ok . I get it. The head space on an AR is under spring pressure and will lock up correctly as long as the all the clearances are correct in the bolt and chamber . Not like a bolt gun where the tolerances are etched in steel and unflexing . Thanks for the head straightening .
Spring pressure does not play a part in headspace. In AR's the barrel-extension contains the counter-lugs on wich the bolt-lugs lock themselves. This extension is permanently threaded to the barrel and therefore the chamber dimensions never change if you move the barrel-extension forward or backwards in relation to the upper-reciever. In a lot of bolt action guns these counter-lugs ar part of the reciever itself. So if you move the barrel towards the reciever you also move it closer to the locking lugs and reduce your headspace. Removing to much material could result in threads that are to short to tighten up your barrel-nut on an AR. Or maybe it makes your camming-pin hit the backend of the recess in your upper reciever.@@orionfixr7713
This is why I buy stripped BCM uppers. They're already machined to a tighter tolence and have to be heated to insert the barrel ext. No sloppy fit and doesn't really require lapping .
headspace is not affected in lapping a reciever.. the barrel has an indexing pin. if you take a little off the reciever that pin still stays in the same place.....
Thanks for posting this video. I feel obligated to add a comment. If that was my build, I’d immediately grab a different stripped upper (preferably BCM because they always run a little on the tighter side) and check if that barrel had that much slop in a different upper. If the barrel was tight in a different upper, the upper you showed in this video would immediately be thrown out or sent back to the manufacturer if it was still in warranty. That much slop is insane. I’ve never seen anything even close to that much slop. If the barrel had that much slop in a different stripped upper, it’d go back to its manufacturer for sure. Either way, at least one of those 2 parts are getting removed from the equation. I have a friend that swears by the 620 LockTite as well, but he uses WAYYYYYY less. A little goes a long way. You are only trying to fill microscopic gaps. Also, I was always told to use the receiver lapping tool in the vertical position, never the horizontal. Because of the forces of gravity, you likely removed more material on the bottom of the upper than the top. I realize the upper appeared not to show this, but that’s likely because the upper was way out of spec and likely required a bit more time with the lapping tool. Had the receiver been vertical, there’s a much higher likelihood of even and ‘true’ lapping. Lastly, I’d DEFINITELY use some aeroshell on the barrel nut. The barrel extension is steel, the upper receiver is aluminum. You definitely need an anti seize between the two. I’d be curious to see a follow up video on if your group size shrank, post lapping.
No antiseize is needed when threads are coated. However, on a seperate topic, when threads are coated m, a loctite primer is need before using actual loctite.
@@5jjt Only reason I'm replying is because I just pulled a barrel where aeroshell wasn't used on a receiver that was coated, and even coated again with cerakote. A lot of galvonic corrosion was present.
My experience shows you get better and more consistent torque if you tighten to 30, then break it lose and re-seat the nut to desired torque. I torque mine 3-4 times. This also helps when using a barrel nut that requires the gas tube to pass through it.
Also a great idea to put some anti seize grease on there to preferably a high heat grease. Or just be a dumbass like the guy in the video and locktite the barrel on and crank the steel nut on to a aluminum receiver dry.
WOW I see a lot of people bitching about using LOCTITE. He is using a LOCTITE brand retainer compound.I use a sleeve retainer on my builds and guess what Criterion Barrels uses it as well in their builds.I am guessing they know a bit more about AR15s then most of us. Criterion uses Loctite 609. Here is what Loctite says about 620. Retaining Compound - high strength. High temperature resistance. LOCTITE® 620 is designed for the bonding of cylindrical fitting parts. The product cures when confined in the absence of air between close-fitting metal surfaces and prevents loosening and leakage due to shock and vibration.
Criterion uses 609 so that an average AR owner can actually disassemble things if needed... 620 is for a gun smith or machinist who has the shop equipment required to actually remove the barrel lol....definitely the right choice ONLY if you have a proper shop.
I will say thank you for posting a video of any kind. I know we all take this for granted now days and always for get that real people took time out of their life to post information for others to enjoy. And like all information throughout time each person must make their own choices about the information. Awesome family to help out.
Having used green loctite a whole bunch in my profession, I can say it’s wonderful stuff , but yes, you can warm it up and get it apart. I would antiseize just about anything I torque and want to disassemble some day. The exception being something that requires loctite on the threads to keep it tight.
Great vid - built ARs for years and I'm pretty sure I just ran across my first noticeably out-of-true receiver face. Got my lapping tools coming in the mail. Looking forward to better alignment and tighter shot groups!
The sudden ending caught me off guard, I was honestly so focused on the video because I plan on building up a .300 blackout Ar-15. I had no idea you could do little things like Lapping the face of the upper receiver extension.
Depends on the tolerances of whoever finishes the receiver. Some manufacturers will intentionally undersize interior diameter specifically to get a tight fit with the barrel extension.
5:00 Headspacing DOES NOT happen between the outside of the barrel extension and the upper receiver. It DOES happer between the bolt and the barrel extension. I know you are probably thinking in terms of a bolt action but the headspace is set when they install barrel extensions on the barrel. headspace gauges are only needed if you install the barrel extension yourself
You need to use Antiseize when working with dissimilar metals. Antisieze contains fine metal powder nickle, copper, etc. Metal is added to be the sacrifical anode, like zinc in an outboard motor lower unit. Your barrel nut is steel, your receiver is aluminum. Two different metals waiting to cause trouble.
Galvanic corrosion requires three things: a noble metal (cathodic) in contact with a less noble metal (anodic) and a common electrolyte, such as moisture. Steel and aluminum are next to each other on the scale and both are on the anodic side. It is true that galvanic corrosion can occur between them, but it would require near constant contact with an electrolyte over a long period of time.
@@SgtJohnRemairez Is it possible? sure, is it likely, no, but depends on how high "high" is in terms of humidity and for how long? I've never had any sort of corrosion on a barrel nut/receiver of an ar-15, even after long term exposure to high humidity levels and getting wet for periods of several days.
Looks like you followed the same path I did--bought the Wheeler kit and discovered it had an unacceptable amount of runout. Then bought the Pacific Tool lapping rod and used the Wheeler lapping compound with it...
There are two types of people in the world. Type one thinks , "You have to do it this way because that's how I was taught, because I was told so!" Type two, thinks.
Type 2 thinks, "This is the right way to it, because through experience and getting it wrong a few times, I learned to the correct way to do it". Right?
Good for you making this video. Lapping the receiver face is a good idea .. not so sure about the Loctite... I might recommend you use aeroshell 33MS for the bbl extension and the bbl nut.
The loctite is to fill the gap between the barrel and the upper. Did you see how loose that barrel was, 620 will fill that gap as long as it's .015 or less. . .Loctite 609 is good for gaps .005 and under. . .The key word here is "bedding"
He lost me with the headspace issue headspace is set by the barrel extension. And where is the anti seize or aero shell grease, he probably just galled the threads on his receiver. If anyone is watching this please continue to look at more content from others between that and common sense you can learn to do things in a way that won’t damage your gear.
Interesting. I have an AR 308 that was wildly inaccurate. Could barely get the barrel off. Heated the receiver and impacted the barrel nut off. The manufacturer had used a red threadlocker on the barrel extension/ receiver, so despite what "expert gunsmiths" are saying below, this is apparently standard for some manufacturers. Had to heat again to remove the barrel from the receiver. New barrel & extension I had was loose as crap in the receiver. I trued the receiver face and high-temp locktighted the barrel extension into the receiver. I didn't know about the 620 at the time. Rifle now shoots sub MOA. Your video is good, and your methods are sound.
Thank you for sharing... as we see below a lot of people judge everything. As a sport shooter I will use any method to give me that one step above the others. Enjoy your new sub MOA rifle!
Thank you for Sharing. I am not claiming to be a gunsmith, but doing a few tricks here and there to get the edge is what I was looking for. Enjoy your rifle and happy Shooting.
My wife helped me change hand guards from the factory plastic to a drop in quad. I didn't have the tool and had to hold the delta ring down by hand and couldn't do it one handed.So she after a couple attempts got the old one off and then placed the new pieces in. for me.While I held it down.
You take material off the face you risk the extension moving to far into the upper (just a few thou) which will cause the feed ramps on the extension to overhang off the ramp cuts (m4 cut) in the upper.
It doesn't matter what torque you like or the receiver/nut you are using. The torque spec starts at 35lbs/ft and at that point you you keep increasing the torque until the gas tube lines up and then stop without exceeding 80lbs/ft. Edit: Ok, with your nut, you don't need to lie up the notches for the gas tube so 40lbs/ft works.
Mostly right. You take the nut to the "best" torque for the barrel and bullet you plan on using within spec, then increase to get the right indexing against your gas tube if needed. Because every barrel is different, you have to determine that through shooting and adjusting. Here's the in-depth explanation of doing that and why, specifically taking about torque at about 12m: ua-cam.com/video/4Si557t-W_s/v-deo.html
I'm an AK guy so I do not know anything about AR's. As a matter of fact, I'm about to do my first AR build ever this coming weekend when I get the parts. Having said that, I have been reading about them and watching videos on UA-cam for the last three days to get familiarized with the platform and I couldn't help to notice that there is a guide pin on top of the barrel extension that meets with a notch on the receiver. My common sense tells me that if you were to remove material from the receiver like in the video, you will only increase the clearance between the receiver and the barrel extension's "stop ring" because the pin on top would not allow the barrel to go in deeper. Does that make sense?
The guide pin on the barrel extension doesn't bottom out in the upper. Causing the barrel to cant. The pin just makes sure the feed ramps are indexed properly. When they put whatever finish and when machining the front of the upper that meets the barrel extension sometimes is not true/square. You only need to lap until you see the lapping tool is lapping all the way around, the front surface is then squared.
Depends on if antiseize is used (Aeroshell 33MS is milspec and perfectly sufficient, no need to get exotic) and also the upper receiver. A bravo company upper and some others are tighter tolerance and you have to heat them with a gun to get a barrel on, so they are difficult to get off. Get yourself a heat gun for reflowing solder and you will find that there isn't really a problem removing it.
Lol, unreal isnt it!? The funny part is, after he got done hollowing out the end of the reciever, with how tight that tool fit in there, the only thing centering the barrel after he squirted all that glue in there was still just the barrel nut, which is absolutely fine thats why it was designed that way. Fuckin ppl.
@@JohnBrowningsGhostit doesnt? You dont think that a lapping tool removes material? Doesnt do what it was designed to do? Im a gunsmith by trade, ill tell you right now this is pointless, the play he showed you is tightened up by the barrel nut pressing the shoulder of the barrel against the reciever, that play in the reciever is simply so itll accept all the different barrels in the world within a spec, if you want a press fit go with a heat fitted barrel, dont try to glue shit in place. Lol
How could headspace be affected by shortening this threaded area? I thought headspace was dictated by the distance between the boltface and the shoulder, which depends upon the lockup of the bolt into the barrel extension, neither of which should be affected by shortening this thread. Am I wrong?
If you shorten it enough, the barrel nut might compress the pin into the receiver face and tilt the barrel downwards (Since the shoulder of the barrel extension wouldn't touch the receiver face). If it tilts enough, headspacing gets affected since the bolt doesn't push directly into the extension, and you get a slightly bigger space at the top, and probably an inability to drive the bolt home. It's an extreme case, but it can happen.
Believe it or not I watched a video where the guy heated up the receiver and then installed the cold barrel. This guy has the right idea facing the receiver face completely flat and true. Although I do mine in a mill making very light passes. Hick tip- this can also be done with a good router and router table
OK, that's for assembly. What about dis-assembly? How do you remove the barrel when that is necessary? Cured Loctite 620 retaining compound does not become elastic until 572°F.
When I bed the barrel I snip a piece of .001 or .0015 shim stock to fit, and cut it down bit by bit until I'm able to very snugly bed the barrel. This keeps me from having to put loctite in there, which I have done and I had some issues with and had to use torch to burn it off to clean it out and redo it again without the loctite.
I recently installed a Midwest Industries free float quad rail handguard on my Bushmaster MOE 5.56 carbine. I already had a low profile Yankee Hill gas block that just fit under my new handguard. I noticed that after I removed the oribinal barrel nut assembly that the barrel wouldn't budge. I couldn't get it out of the receiver. I didn't really try since I wasn't changing the barrel, but why would it have been stuck in the upper receiver like that?
I'm no gunsmith nor do I pretend to be but I've got the targets to prove this method works. I'm now mounting all my barrels with green locktite and when I can fit it, .001 shim stock. Yes, you can still remove the barrel with a LITTLE heat. No need to get out the cutting torch. The little blue bottle from the hardware store works perfectly. Again, use as little heat as possible to remove the barrel.
It will not affect head space and you should do it vertically so the lapping tool rides flat. I would check and find the slop. Probably a bad upper. Discard it. I would never locktite
@@carlosmartin3587 , yes, I lightly lap the finish off the upper always. But if a upper had that much slop in it I would discard it. I beleive(without rewatching) the video stated dont lap to much or it could effect headspace, which is incorrect. The upper has nothing to do with it. The bolt slams home/into battery and headspace is from bolt face to datum line. So removing material from the front of the upper threading just moves the gas tube back a few .001. My main point was lap the upper in a vertical position so the tool rides flat, which is squarer to the bore line. Doing it horizontally I noticed the tool canting downward.
Head spacing is already determined from bolt and barrel lockup. NOT the receiver trimmed back. You "might have feeding issues if ramp cuts in receiver does not match up to barrel. But headspace IS NOT SCREWED UP JUST BY LAPPING
I take it that making sure the barrel surfaces and barrel nut surface are flat is not as important. Probably because they're steel and likely machined better?
That is a lot of movement. I have done quite a few builds for myself and friends and I have never run into that kind of slop. Always super tight fit. On another note, I doubt its even an issue when barrel nut is torqued. Only thing i ever put on there is aeroshell. Good tip on torque wrench and adapter being at 90 DEGREES. The only thing i would recommend is that after torquing the barrel nut, break it and torque again to account for any thread deformities or foreign material in threads. Now for my personal 2 cents: I have an accurate AR in .308 (1/2'' groups @100). Great rifle. Most of my modern rifles achieve 1'' groups or less. I will take 2'' MOA all day out of an ar-15 though. Better platforms for precision rifles and i consider 1'' moa or less a precision rifle.
When you inserted the barrel into the upper you should've turned it back and forth to evenly distribute the 620 between the barrel and receiver. . . .You also only faced off the receiver so it has 50% contact which also isn't ideal . . .I want over 75% contact surface whenever I lap anything, 90% is even better, 100% the best. . .
This is the issue here, barrel or upper is out of spec.... this is a backwoods fix more than it is proper gunsmith advice. Don't even need to be a quality upper, i have a $40 beer creek upper and a aero precision upper that were both cheap as i could find at the time and had zero issues like that. Hell i had to tap my barrel in on the last one....
Agreed. That's a lot of slop and I don't think he read the specs for Loctite 620. It is good up to .008" - he might have had more than that. Kind of a hack job....
I think his barrel is out of spec. The lapping tool appeared to fit firmly and had no visible wobble like his barrel did. He noted he had to lube it to get it in smoothly.
@@coolkid6364 Just be aware that a tight receiver to barrel extension fitment alone doesn't mean that they are mating properly. You can very well have a "stacking" of high points on both components that are leading to what can feel like a tight fit. Loctite to fill in the "voids" as it were is still a good idea, and it's been demonstrated time and time again to to have a measurable impact on accuracy. There's good information on this on the SOTAR FB group if you're interested in a more technical deep dive into this platform.
For the best accuracy the barrel must not move at all when attached to the upper. Having only a true upper face will not prevent the barrel from moving. With two very flat mating surfaces the barrel can still move around in a circle. Granted, very small amount of movement. To remove the ability to move around you need a retaining compound or an interference fit. The LocTite 620 is only good up to 200C(392F) so it may not be the right choice for a barrel that will get very hot, I guess that depends on how you'll shoot it. Interference fit is really the best way to "lock" the barrel to the upper. If you are not in competition then most likely none of this really means much. If you are a super critical hobby shooter then lapping should suffice. If you want to bond the extension into the upper, Extreme Heat JB Weld would be better than the 620. If I wanted to do this for accuracy holding I would get interference fit upper and the lap it true. Heat upper (oven, etc) and chill the barrel extension end in ice water. The sec just before install wipe the extension with full synthetic motor oil then wipe again with dry lint free cloth, this oil will to some extent fill tiny pores and stay there helping to remove mating dead space between upper and barrel. One key step is immediately after mating the two pieces is to get a barrel nut on there and torque it to spec. Let it come back to room temp then redo the barrel nut stuff, etc. And to note, you can make Aeroshell grease with simple Lucas lithium and some Moly powder. But, any lube/grease on the upper threads is better than nothing at all.
@@grammatoncleric550 "0" weight SYNTHETIC motor oil is the preferred lube for all weather (especially sub zero) as its viscosity never changes and it stays where you put it. In the past, even that red auto trans fluid was directly marketed as a wonder lube for guns. It failed because it evaporates over time.
Marine-Tex is better at more than 500C. Also a lot less shrink, and more impervious to chemical decomposition making it a great choice for galvonic prevention.
Did you inspect the upper to confirm that the face was not perpendicular to the bore prior to lapping? It might not have needed it and you could’ve lapped it out, a hand tool will not work as good as the cnc that machined that face
That barrel looks like a Century arms set up. I purchased a FAL years ago,thank god i didnt shoot the pos. The barrel was loooosssseee as could be when i took it out to clean it.Took it to mY GS and he showed me the washer they used to repair set back THANK God for DS arms front end . C.I.ARMS told me to piss off.
FWIW, lapping the front of the receiver is only going to get you part of the way there. That's a really loose fit. You need to add shim stock or get a custom barrel extension from BAT that's oversized the correct amount to fit your upper. You may not expect 1/4 MOA, but if your using a single round sled, an AR is capable of it. If you're ripping rounds out of a loaded mag, 1/2 MOA is pretty good in my book.
Torque then loosen 2-3 times before final torque. Use GMD Or some type of molybdenum grease like aero shell on the threads. You also want at least 40 to 65 pounds of torque or all of this bedding doesn't benefit you at all.
@@timothymickal8172 - Torque and loosen 2-3 times before final torque is only a "must do" when the receiver, or barrel nut, or both are brand new. Once it's been done once you don't have to do it again - the threads don't get any more seasoned. And judging by the wrench marks on the nut, those components were both well used.
Quality barrel and quality upper will fit correctly, have very little play and, when the barrel nut is torqued down, prevent any movement. Ammo and barrel have an effect on the accuracy far more than any lapping.
That barrel extension should be snug or tight fit in the upper receiver if precision accuracy is the goal. You should measure to see if the hole of the receiver is oversized or the barrel extension is under sized and replace the out of spec part. Or you can shim it with a feeler gauge set using the thickness for your need. Folding the shim around the barrel extension. Cheap solution! (GearWrench Feeler Gauge size 32) This is a nice tip though, thanks for sharing. It should improve accuracy by supporting the under sized barrel extension all around it. 😉👍🏼
If your barrel wiggles in the receiver then you need a different receiver, a higher quality one. If tge tolerances are off in tge front, then they are most likely off over the entire receiver. A good quality upper, lower, and barrel will provide better results that bedding will.
Only thing I can add is why not place the upper in the vise vertical while you're lapping the face ? Let gravity work for you. The pressure you were applying to the lapping tool plus the torque to make it turn is cocking the tool as much as it would go and is probably why it only surfaced the lower left of the receiver. I'm not expert but I have worked with machine shop practices and built a few ARs in my time. Take it for what it's worth . Just friendly advice .
Thank you, I will try it that way on my next build and see how it works. That is why we make these videos, to share tips and tricks of the trade. Stay safe out there
It removed part of the anodizing because the milling of the threading wasn't true or the thickness of the anodizing was not uniform. Not because of torque on the tool.
I have found that some uppers i put together need like 20 something clicks of adjustment on the rear sight to get zeroed while some require a handful of clicks. I assume lapping the upper would square up the fit and result in less windage adjustment on the rear sight. Does anyone have experience with this problem?
I have heard this along with fitting gas tube and floating a bolt carrier and fine headspacing a bolt can produce .25-.5 MOA grouping from premium barrels like criterions and Noveskes.
Great video... Thanks for sharing.... Love all the critics.... People like "MC" make life exhausting... From one veteran to another I have found that those who feel compelled to go out of their way to "immortalize" themselves usually possess less than half the shit they want you to believe they know!!!
If you want to increase accuracy spend about an extra $100 and get a VLTOR MUR upper. Did you see the way that Barrel just slides right into the upper without any resistance? I have assembled two different builds with this receiver and in both instances I had to take a board and a hammer and tap it in because it was so snug. That is the key to having a good Barrel install without movement. Also this is an aerospace company and they have very precise Machining plus the receiver is done with extra metal in critical places so it is more rigid, it weighs more than a mil spec receiver even though it is a forged receiver not Billet. I'm telling you if you want to build an accurized rifle this is the receiver to get and you don't have to deal with any of this nonsense with lapping and putting thread Locker on the barrel. All you need to do is put either Molly grease or some anti-seize and tap it together and torque it down. I have been using the moly grease, but I've heard good things about some certain anti-seize compound. The VLTOR receiver is about $160 to $170. You can get one without forward assist for a little cheaper but I always got the forward assist.. There is also no rough sound when you work the action with this receiver, it is smooth as silk right out of the box. There is a reason this receiver costs more money and honestly the price is not astronomical or anything.
Can you remove a loctite bedded barrel without harming the upper? I’ve read you can use a lot of heat but wouldn’t that screw with the aluminum tempering?
Yes, I use a heat gun (no torch needed). I just did one today, a couple minutes with a heat gun and it came right out. The right Loctite to use is 620. It's a bearing retaining compound. As Loctite says, "LOCTITE® 620 is a retaining compound designed for the bonding of cylindrical fitting parts."
Im sorry im very new to all the building and painting parts of an AR15 so when i ask why you didnt show us an comparison of the play ,after you lapped the upper ,dont get upset?You wiggled it and showed us teh play yet you didnt, show us the play after the fact? Just curious???
The ar-15 platform headspaces with the bolt to barrel extension not the barrel to reciever. Now if you take off too much material you may run into feeding issues but headspace will not be affected by it.
That's exactly what I was thinking
Could you just hit the surface with a stone
@@Jayis_preppy that can be resolved with a shim or shims under the barrel extension - that is if the barrel extension protrudes into the receiver.
Many are under the impression that a locking material like LocTite is needed- IT IS NOT. The torque holds the nut to the receiver. I have never, ever seen a loose barrel in the military. As an armorer I have seen thousands of overused guns. YES the facing of the upper is needed especially for long range shooting as it aligns the barrel to the upper. Facing will NOT change the headspace as the headspace is integral with the barrel. The barrel MUST fit snug to the upper and the best fit is a slip fit. We used .001 stainless shim stock wrapped around the barrel extension to fit sloppy barrels for accuracy guns as even .001 barrel shift when assembling will cause a lot of scope issues at long range. Within MIL-SPEC is a joke as it is the MAXIMUM and minimum allowable specification and still work.. FYI The shear point for a barreled upper is the last thread on the upper behind the barrel nut.
Thanks for taking the time to write this.
stainless shims dont disintegrate over time from the cooling/heating cycling?
@@atranimecs If that is a question then NO. No rust or deterioration at all.
In my case though it does make a difference. I had Ruger MPR that I got rid off. After a while the barrel nut got so loose that it could have been taken off with a finger.
Luckily I found that out before anything catastrophic. I say DEFINITELY blue lactite the threads. My 2 cents
I never use loctite but i do use anti-sieze on the threads because too many have come to my shop for cerakote and people do not take care of their weapons and they are rusted fast and gauled to the aluminum threads
The face doesn't change the headspace. The headspacing is a function of the internal locking lugs.
“We’re goin to add a couple drops of the green locktite”
***paints barrel extension like Michelangelo
What no silicone ?
Seriously overdone
Hahaha
I got the feeling he used an awful lot of loctite.
I noticed two things and I'm not saying he's wrong:
- he didn't use any anti-seize compound or lithium grease on barrel nut threads
- most videos show tightening, then loosening of barrel nut 2-3x before final seating
@@escapedfromnewyork I believe he's just using the loctite as a bedding compound to remove the looseness and circular play in the barrel. It's not the adhesive type of loctite for securing threads. The Barrel nut is being used to apply even pressure between the barrel extension and receiver so that the loctite cures in a manner somewhat consistent with the rifles final assembly. Once the locktite cures, I imagine he could pop the barrel nut off and do the final assembly steps (anti-seize on threads, timing and seasoning/torquing the barrel nut, etc).
Only kinda assuming some of this as the great UA-cam Algorithm took me down a rabbit hole of "how to's" of bedding and free floating bolt action hunting rifles before finding people using loctite 620 to bed ar15 barrel extensions.
(1) You'll not have head space issue from lapping the front of the receiver. The AR-15 head space is between the bolt and the barrel extension. Even taking a millimeter off (which is ridiculous) the head space will not change. In the extreme, the hammer will not hit square on the firing pin because the barrel is far back, but you need to take off an insane amount of material to get to that point.
(2) The mating of the front of the receiver and the barrel extension's recoil ring is actually NOT SO IMPORTANT. What is more important is the clearance between the barrel extension's outer surface and the inner surface of the receiver. This is what allows the barrel to move around. It is also why clamping receivers like the LMT ARs and the SCAR -- which by design have ZERO slop in this regard when tightened -- are generally more accurate.
(3) Shimming the barrel extension and packing the remaining clearance with Loctite 620 will be responsible for the overwhelming majority of the accuracy gain, finishing the front of the receiver and/or the rear of the barrel extension recoil ring is SECONDARY. It's nice to do, but not ultimately all that crucial.
A scar is not more accurate than a high quality AR, not even close. In fact it's closer to that of an inexpensive AR but not total bottom end.
@@actionjksn The SCAR will always have less inaccuracy from the barrel receiver interface than an AR because there will be zero mechanical wander of the barrel. It is a piston gun though which has less consistent harmonics than a DI gun. That said, the SCAR has a hammer forged barrel which is not all that common on ARs except those from SIGs and HKs, and I find it more accurate than ARs in general mainly because of barrel quality being higher than the average AR.
@@dwightlooiMy 6920 shoot circles around the 16S. And that’s it’s factory match and hand loads.
16S is 2 MOA at best with good tailored loads. The 6920 hovers around a minute.
He is confusing a AR barrel with a Bolt action barrel.
Excellent video.
Very educational.
Thank you.
Just for thoughts....Do all the work vertical. Lapping, bedding, tightening, with receiver and barrel sandwiched inside the plastic receiver block, receiver block vertical. There are much more sophisticated ways of centering your bcg,bolt,receiver,barrel if you have a machine shop and a lathe. But this is how I do it in the home armory. It's good enough for .75 MOA if everything else is working for you.
BEDDING. Apply the green “expanding” Loctite (620) on the outside wall of the barrel extension for proper bedding, make sure the green coating is even around. The green stuff is not for threads yo. Still in the vertical position install barrel. Then install bcg and bolt to locking position. Tape back of bcg and receiver to give extra hold. Put some aeroshell or red and tacky inside the receiver extension nut. Wipe of any excess green stuff from the mating surface of the barrel and receiver. Tighten Receiver extension nut to 20lbs only with unit still in vertical plastic receiver block. Drop out bcg and wipe any excess green out of the inside mating surface of receiver and barrel extension. Let sit for a few hours to firm up. Remove unit from crappy plastic receiver vise block and install unit on steel barrel extension wrench, wrench mounted vertically in vise. Crank down receiver extension nut to 25/30/35/40 loosen each time. Stop at 40lbs. Most nut wrenches add a few pounds (3-8) to the torq reading anyway. Let sit vertical for a few hours. Check for any green stuff inside receiver. Test bcg/bolt fitment again, should drop in real smooth. This is assuming that you removed as little material as possible during lapping…LAPPING. If you over-lapped it then it pushes the rear of the bcg backwards in the receiver, check to make sure all components are working properly. Over lapping is not a good thing. Just a little bit is all it needs. When you see exposure of silver down there between the 6pm and 9pm position during lapping is because the lapping is typically done clockwise and horizontal with gravity pulling the tool down on the system. Horizontal lapping is how they show you on the Brownell’s video and many other videos. It’s dead wrong. Gravity is working PERPENDICULAR against the centering of the system by pulling down on the drill and the tool. And the drill operator is adding a lot of error (many thousandths) to the system by holding the drill horizontal. In the vertical you can spin the tool gently by hand and let gravity do the work. Just have a little patience. Or use a low rotation battery powered bit driver that is symmetrical with the tool and vertical, 200 grit lapping compound. A hand drill is not a symmetrical tool, especially not in the horizontal….SUMMARY. The whole idea is to keep the moving parts centered together, remove gravity as a perpendicular force during install, and don't over torq your barrel nut. It's NOT needed above 40lbs. Lastly you don't need to lap the receiver down to aluminum if not warranted. So many peeps like to grind that baby down. Just lap the hard coat until you see even removal on the hard coat, if possible. The less exposed aluminum the better. The hard coat actually helps to reinforce the aluminum extension lip during the life of the rifle. Cheers.
I’m just a hobbyists but my thought process aligned with your comment. I thought this was common knowledge until I read a lot of comments on UA-cam and forums.
Great video! I think most of the people leaving comments claiming to be "Professional gunsmiths" and slamming the use of loctite 620 are missing the point. In the video, this man is not using threadlocker on the threads. He is using cylindrical sealer to close the gap on the barrel shaft. I didn't see him put any "Thread locker" on the threads. Also, just because it's Loctite brand doesn't mean that it's threadlocker. That company makes more then just thread locker.... LOL
Exactly
..and that's 'bedding' an AR barrel.
Lapping is the procedure to make ready for bedding.
@Neito Kradavish considering all that hot gas is being directed to right in front of it via the gas tube, im uncertain of your assertion here. BUT i more than willing to throw my heat gun on my gun next time i do a mag dump, just out of curiosity more than anything else.
Yep it's called retaining compound and that's precisely what it's for, retaining and taking up a small gap, it's almost as strong as a weld and is a ferocious bond pretty crazy stuff
@Purple Haze the barrelled flange that meets up with the receiver is already squared up from factory. It's squared up when the barrel is formed and would be almost impossible to have that flange NOT square unless someone completely failed in the making of the barrel. The receiver is not square. You lap the receiver to get it square, which you can actually see by the lapping compound marks and then the barrel flange sets square to the receiver. The barrel nut doesn't have to be totally square because it's just compressing the two surfaces together. So there's are only two surfaces that need to be square and one (the barrel flange) already is square. The barrel nut only has to be close (which it is) for it to all pull together close. Then the retaining compound fills the gap between the barrel tube and receiver.
Kenny Wooldridge Is anybody familiar with Loctite NS 5540 High temp for Threads and Flanges? With a service temperature of 100 to 1300 degrees Fahrenheit?
I stopped watching after he said "if you take off too much you'll run into headspacing issues" this right there shows he doesnt know much about the AR15 platform
@@teddysurf Because the headspacing is set with the barrel extension at time of manufacture, the upper receiver doesnt have anything to do with headspacing.
@@teddysurf The BCG locks into the extension on the barrel which is already installed before you get it. Look into it pal, because it seems like you dont know as much as you think. This is not a bolt gun. Now have a nice day.
@@teddysurf Im sorry, I dont have any youtube gunsmithing degrees... My experience is in real life...
@@teddysurf the headspace is permanently set by the barrel extension and pinned from the manufacturer. Lapping the face of the upper, in itself could be questionable without chucking it up in a lathe and finding the true centerline. You could lap it all day and the worse you could do is mess where the barrel extension meets the feed ramps on the inside of the upper. Still would not change head space.
Ar15 headspace has zero to do with the upper receiver. You can check headspace with just a barrel (with extension) and a bolt, with no receiver even in the same room. One of the benefits of the design is that receiver variations don’t really matter, so long as the bcg and barrel are on the same axis.
You need shims for that wiggle my friend! Not a lapping job. The lapping does help but that wiggle is still there. American Gunsmith back in 2013 had a two part article written by Mr. Carlos addressing this issue. His article “Barrel Extension Diameter In The AR 15” is exactly what you need to fix that wiggle. Cheers.
Informative. Why didn't you put any anti-seize on the threads?
Agree. I would rather use anti-seize compound, rather than loctite between the barrel and upper interface. Same reasoning for the steel nut (if it is indeed steel) to the aluminum threads. Also, I don't want to have to heat the joint to "break" the loctite if I need to strip it down.
Remember when torquing to have the tool at 90 degrees to the torque wrench other wise you will be multiplying your toque. This is taught in aviation in getting the correct torque or you will have to calculate the extra leverage and reduce it on the torque wrench.
I don't think it is multiplying your toque, but yes, it does add leverage
Well done video.
I am a certified AR-15 Armorer, multiple times over. I have the same lapping tool. Only two minor things I do differently.
1. I lap with upper receiver vertical.
2. I add Aeroshell 33 MS to the upper receiver barrel nut threads.
Again, great video!! Thank you for taking the time and all the effort (Wifey and Daughter included, of course) to make it and then post it.
Thank you for the input... it was a fun project...
You aren't the only one who uses locktite in the upper, but I'd suggest a release agent on upper. Tightens the groups up considerably. Good vid.
Ethan
Good suggestion.
Aeroshell grease sure. However, the fact that would use locktite on a barrel extension tells me that you're not really certified. If the receiver is that loose, then you need either one of two things. One, a new upper receiver. Two, a new barrel extension; which you might as well replace the whole barrel (unless you have a lathe to set the headspace again). Two is way more work, but may provide a tighter fitment. However, 1 is the go to since it's easier to get a new upper.
I couldn't do the slop, I'd try to find a different upper before I slathered any goop on the barrel extension...For some reason billet receiver sets had slop with my Proof Research barrel, BCM uppers and Bootleg uppers were snug..
i just have to point out a few things . i build target uppers . and have done around 400 of them . first do not use the lapping tool horizontally . almost everyone on youtube does it wrong . put it in the vice vertically and it will be a more accurate lapping . do not use a drill ! or you will take off to much ! i never use loctite on barrels . get some .001 or .002 stainless steel shim stock and use it . it is cheap . wrap shim stock on barrel extension . till it is .001 over the receiver opening . than use a propane torch and heat the barrel nut thread up . 5 to 7 slow turns of the upper . do not change the color of the metal when heating . just get it to expand . and slide it on the barrel . make sure the barrel is in the vice before heating the upper . now let it cool down , and it will be ' bedded ' nice and tight and square to the upper . learned this and more from my cuz . not going to give his name . but people pay 3 to $4,000.00 for his ars and even more for his 1911's . almost all of his target uppers are built by me . and use anti seize on the barrel nut . makes it a lot eayser to get it back off if you need too .
Removing to much does not affect the headspace.
It will only affect the length of you threads.
How do you figure it doesn't affect the head space ? If you remove .005" , does that not move the barrel extension back .005" ? And wouldn't that move your headspace back .005" ? I'm confused .
Sure it moves the barrel extension back.
It also moves everything else conected to the extension back ,005"
Headspace is determined by the space between the bolt-face and the shoulder of the chamber, this dimension does not change.
@@orionfixr7713
I might have miss spoke in regards to head space. I was trying to explain the position of the bolt in the upper receiver. I am used to working bolt actions and getting the bolts to function properly in the action and barrel. It has been my experience that If you remove to much then the Clocking of the barrel nut (depending on type) may be affected to the point you may need shims to correct.
@@HarmJW77 Ok . I get it. The head space on an AR is under spring pressure and will lock up correctly as long as the all the clearances are correct in the bolt and chamber . Not like a bolt gun where the tolerances are etched in steel and unflexing . Thanks for the head straightening .
Spring pressure does not play a part in headspace.
In AR's the barrel-extension contains the counter-lugs on wich the bolt-lugs lock themselves.
This extension is permanently threaded to the barrel and therefore the chamber dimensions never change if you move the barrel-extension forward or backwards in relation to the upper-reciever.
In a lot of bolt action guns these counter-lugs ar part of the reciever itself.
So if you move the barrel towards the reciever you also move it closer to the locking lugs and reduce your headspace.
Removing to much material could result in threads that are to short to tighten up your barrel-nut on an AR.
Or maybe it makes your camming-pin hit the backend of the recess in your upper reciever.@@orionfixr7713
I'd really like to see how solid the upper and barrel are after the loctite has dried and with the barrel nut off.
This is why I buy stripped BCM uppers. They're already machined to a tighter tolence and have to be heated to insert the barrel ext. No sloppy fit and doesn't really require lapping .
Even after heating with a propane torch it's still a pain in the ass to get together from my experience very tight tolerances tho
Eric Hayes I have also noticed this in the aero Percision upper receivers very tight fitting on the barrel extension.
Yep. Same w/Aero Precision, and Spikes. That barrel isn't moving after applying AeroShell, and setting in the upper.
exactly..best uppers for the money..good tight fit
headspace is not affected in lapping a reciever.. the barrel has an indexing pin. if you take a little off the reciever that pin still stays in the same place.....
Thanks for posting this video. I feel obligated to add a comment. If that was my build, I’d immediately grab a different stripped upper (preferably BCM because they always run a little on the tighter side) and check if that barrel had that much slop in a different upper. If the barrel was tight in a different upper, the upper you showed in this video would immediately be thrown out or sent back to the manufacturer if it was still in warranty. That much slop is insane. I’ve never seen anything even close to that much slop. If the barrel had that much slop in a different stripped upper, it’d go back to its manufacturer for sure. Either way, at least one of those 2 parts are getting removed from the equation. I have a friend that swears by the 620 LockTite as well, but he uses WAYYYYYY less. A little goes a long way. You are only trying to fill microscopic gaps. Also, I was always told to use the receiver lapping tool in the vertical position, never the horizontal. Because of the forces of gravity, you likely removed more material on the bottom of the upper than the top. I realize the upper appeared not to show this, but that’s likely because the upper was way out of spec and likely required a bit more time with the lapping tool. Had the receiver been vertical, there’s a much higher likelihood of even and ‘true’ lapping. Lastly, I’d DEFINITELY use some aeroshell on the barrel nut. The barrel extension is steel, the upper receiver is aluminum. You definitely need an anti seize between the two. I’d be curious to see a follow up video on if your group size shrank, post lapping.
No antiseize is needed when threads are coated.
However, on a seperate topic, when threads are coated m, a loctite primer is need before using actual loctite.
@@5jjt Only reason I'm replying is because I just pulled a barrel where aeroshell wasn't used on a receiver that was coated, and even coated again with cerakote. A lot of galvonic corrosion was present.
My experience shows you get better and more consistent torque if you tighten to 30, then break it lose and re-seat the nut to desired torque. I torque mine 3-4 times. This also helps when using a barrel nut that requires the gas tube to pass through it.
Also a great idea to put some anti seize grease on there to preferably a high heat grease. Or just be a dumbass like the guy in the video and locktite the barrel on and crank the steel nut on to a aluminum receiver dry.
WOW I see a lot of people bitching about using LOCTITE. He is using a LOCTITE brand retainer compound.I use a sleeve retainer on my builds and guess what Criterion Barrels uses it as well in their builds.I am guessing they know a bit more about AR15s then most of us. Criterion uses Loctite 609.
Here is what Loctite says about 620.
Retaining Compound - high strength. High temperature resistance.
LOCTITE® 620 is designed for the bonding of cylindrical fitting parts. The product cures when confined in the absence of air between close-fitting metal surfaces and prevents loosening and leakage due to shock and vibration.
Criterion uses 609 so that an average AR owner can actually disassemble things if needed...
620 is for a gun smith or machinist who has the shop equipment required to actually remove the barrel lol....definitely the right choice ONLY if you have a proper shop.
@@atranimecs 620 is not that hard to get apart. Just did one today with a heat gun.
@@jbmillard Notice a proper shop would have something like a heat gun or blowtorch like I said. average joe may not have either in their garage.
I will say thank you for posting a video of any kind. I know we all take this for granted now days and always for get that real people took time out of their life to post information for others to enjoy. And like all information throughout time each person must make their own choices about the information. Awesome family to help out.
If your on UA-cam educating yourself for free then blame yourself first if something doesn’t work. Lol
You forgot anti-seize on the barrel nut
well, you might want to use anti-seize on the threads, BUT with GREEN loctite in the upper he likely isn't taking that off again for life...
He shouldn't be using loctite on that upper/barrel anyways!
antiseize will just burn off need to use a moly based grease hi temp like aeroshell33 ms
Having used green loctite a whole bunch in my profession, I can say it’s wonderful stuff , but yes, you can warm it up and get it apart. I would antiseize just about anything I torque and want to disassemble some day. The exception being something that requires loctite on the threads to keep it tight.
@@MC-px9eq Yes he should. Know what you are talking about before you talk.
Great vid - built ARs for years and I'm pretty sure I just ran across my first noticeably out-of-true receiver face. Got my lapping tools coming in the mail. Looking forward to better alignment and tighter shot groups!
The sudden ending caught me off guard, I was honestly so focused on the video because I plan on building up a .300 blackout Ar-15. I had no idea you could do little things like Lapping the face of the upper receiver extension.
In the UK we would call that a " prick in a bucket " fit !
Never seen a barrel that loose. When I did mine it was as tight as my first lay!
Depends on the tolerances of whoever finishes the receiver. Some manufacturers will intentionally undersize interior diameter specifically to get a tight fit with the barrel extension.
Good to see Darth Vader picking up new hobbies
lol, the heavy breathing
5:00 Headspacing DOES NOT happen between the outside of the barrel extension and the upper receiver. It DOES happer between the bolt and the barrel extension.
I know you are probably thinking in terms of a bolt action but the headspace is set when they install barrel extensions on the barrel. headspace gauges are only needed if you install the barrel extension yourself
You need to use Antiseize when working with dissimilar metals. Antisieze contains fine metal powder nickle, copper, etc. Metal is added to be the sacrifical anode, like zinc in an outboard motor lower unit. Your barrel nut is steel, your receiver is aluminum. Two different metals waiting to cause trouble.
Galvanic corrosion requires three things: a noble metal (cathodic) in contact with a less noble metal (anodic) and a common electrolyte, such as moisture. Steel and aluminum are next to each other on the scale and both are on the anodic side. It is true that galvanic corrosion can occur between them, but it would require near constant contact with an electrolyte over a long period of time.
@@edwardlance2379 Can that occur if the firearm is stored under high humidity conditions most of the time?
@@SgtJohnRemairez Is it possible? sure, is it likely, no, but depends on how high "high" is in terms of humidity and for how long?
I've never had any sort of corrosion on a barrel nut/receiver of an ar-15, even after long term exposure to high humidity levels and getting wet for periods of several days.
@@edwardlance2379 About 15% of the upper barrels I pull have corrosion on them. I've pulled hundreds. This is in the desert.
Looks like you followed the same path I did--bought the Wheeler kit and discovered it had an unacceptable amount of runout. Then bought the Pacific Tool lapping rod and used the Wheeler lapping compound with it...
There are two types of people in the world.
Type one thinks , "You have to do it this way because that's how I was taught, because I was told so!"
Type two, thinks.
Type 2 thinks, "This is the right way to it, because through experience and getting it wrong a few times, I learned to the correct way to do it". Right?
What happened to tightening the barrel 3 times?
Good for you making this video. Lapping the receiver face is a good idea .. not so sure about the Loctite... I might recommend you use aeroshell 33MS for the bbl extension and the bbl nut.
The loctite is to fill the gap between the barrel and the upper. Did you see how loose that barrel was, 620 will fill that gap as long as it's .015 or less. . .Loctite 609 is good for gaps .005 and under. . .The key word here is "bedding"
@@z50com Cool... That works I guess.
He lost me with the headspace issue headspace is set by the barrel extension. And where is the anti seize or aero shell grease, he probably just galled the threads on his receiver. If anyone is watching this please continue to look at more content from others between that and common sense you can learn to do things in a way that won’t damage your gear.
Interesting. I have an AR 308 that was wildly inaccurate. Could barely get the barrel off. Heated the receiver and impacted the barrel nut off. The manufacturer had used a red threadlocker on the barrel extension/ receiver, so despite what "expert gunsmiths" are saying below, this is apparently standard for some manufacturers. Had to heat again to remove the barrel from the receiver. New barrel & extension I had was loose as crap in the receiver. I trued the receiver face and high-temp locktighted the barrel extension into the receiver. I didn't know about the 620 at the time. Rifle now shoots sub MOA. Your video is good, and your methods are sound.
Thank you for sharing... as we see below a lot of people judge everything. As a sport shooter I will use any method to give me that one step above the others. Enjoy your new sub MOA rifle!
Thank you for Sharing. I am not claiming to be a gunsmith, but doing a few tricks here and there to get the edge is what I was looking for. Enjoy your rifle and happy Shooting.
You also need to use anti- sieze on your upper reciever threads.
Hello from NE Tacoma. Thanks for all the valuable info.
My wife helped me change hand guards from the factory plastic to a drop in quad. I didn't have the tool and had to hold the delta ring down by hand and couldn't do it one handed.So she after a couple attempts got the old one off and then placed the new pieces in. for me.While I held it down.
I usually just read mine a bedtime story and it goes right in.
I lick mine.....
You take material off the face you risk the extension moving to far into the upper (just a few thou) which will cause the feed ramps on the extension to overhang off the ramp cuts (m4 cut) in the upper.
It doesn't matter what torque you like or the receiver/nut you are using. The torque spec starts at 35lbs/ft and at that point you you keep increasing the torque until the gas tube lines up and then stop without exceeding 80lbs/ft.
Edit:
Ok, with your nut, you don't need to lie up the notches for the gas tube so 40lbs/ft works.
Mostly right. You take the nut to the "best" torque for the barrel and bullet you plan on using within spec, then increase to get the right indexing against your gas tube if needed. Because every barrel is different, you have to determine that through shooting and adjusting.
Here's the in-depth explanation of doing that and why, specifically taking about torque at about 12m: ua-cam.com/video/4Si557t-W_s/v-deo.html
@@FadingSwordsman In the video that you posted he's not talking about the Barrel Nut.
I'm an AK guy so I do not know anything about AR's. As a matter of fact, I'm about to do my first AR build ever this coming weekend when I get the parts. Having said that, I have been reading about them and watching videos on UA-cam for the last three days to get familiarized with the platform and I couldn't help to notice that there is a guide pin on top of the barrel extension that meets with a notch on the receiver. My common sense tells me that if you were to remove material from the receiver like in the video, you will only increase the clearance between the receiver and the barrel extension's "stop ring" because the pin on top would not allow the barrel to go in deeper. Does that make sense?
Perfect sense.
The guide pin on the barrel extension doesn't bottom out in the upper. Causing the barrel to cant. The pin just makes sure the feed ramps are indexed properly. When they put whatever finish and when machining the front of the upper that meets the barrel extension sometimes is not true/square. You only need to lap until you see the lapping tool is lapping all the way around, the front surface is then squared.
Nice presentation, my question is how does it come apart later for barrel upgrade or maintenance
It doesn't
How much difficulty will be encountered when it's time to remove the barrel?
Depends on if antiseize is used (Aeroshell 33MS is milspec and perfectly sufficient, no need to get exotic) and also the upper receiver. A bravo company upper and some others are tighter tolerance and you have to heat them with a gun to get a barrel on, so they are difficult to get off. Get yourself a heat gun for reflowing solder and you will find that there isn't really a problem removing it.
a little heat from a torch, easy pezy
@@chrismcrae4652 ummm a pretty big torch...that is highly heat resistant compound
i go 50 lbs of torque..its a great universal for me. havent had any issues. great accuracy. idk if id loctite a barrel in though.
For those that don’t know, nitromethane is the solvent for loctite.
Where did you learn your gunsmithing skill? Lot of miss information on here
China?
Lol, unreal isnt it!? The funny part is, after he got done hollowing out the end of the reciever, with how tight that tool fit in there, the only thing centering the barrel after he squirted all that glue in there was still just the barrel nut, which is absolutely fine thats why it was designed that way. Fuckin ppl.
What exactly do you think he did that was wrong?
@@nategaudette4228 the lapping tool has no bearing on how the barrel extention fits to the interior of the receiver.
@@JohnBrowningsGhostit doesnt? You dont think that a lapping tool removes material? Doesnt do what it was designed to do? Im a gunsmith by trade, ill tell you right now this is pointless, the play he showed you is tightened up by the barrel nut pressing the shoulder of the barrel against the reciever, that play in the reciever is simply so itll accept all the different barrels in the world within a spec, if you want a press fit go with a heat fitted barrel, dont try to glue shit in place. Lol
I use BCM uppers for exactly the reason behind the slop we see here. Yeah you have to heat one and freeze the barrel but the fitment is great.
How could headspace be affected by shortening this threaded area? I thought headspace was dictated by the distance between the boltface and the shoulder, which depends upon the lockup of the bolt into the barrel extension, neither of which should be affected by shortening this thread. Am I wrong?
you are correct
If you shorten it enough, the barrel nut might compress the pin into the receiver face and tilt the barrel downwards (Since the shoulder of the barrel extension wouldn't touch the receiver face). If it tilts enough, headspacing gets affected since the bolt doesn't push directly into the extension, and you get a slightly bigger space at the top, and probably an inability to drive the bolt home. It's an extreme case, but it can happen.
Believe it or not I watched a video where the guy heated up the receiver and then installed the cold barrel.
This guy has the right idea facing the receiver face completely flat and true.
Although I do mine in a mill making very light passes.
Hick tip- this can also be done with a good router and router table
Thanks for showing a very good example of how to do it correctly! I’ll bet it did make a diff in Moa.
Thanks for showing us, appreciate it
OK, that's for assembly. What about dis-assembly? How do you remove the barrel when that is necessary? Cured Loctite 620 retaining compound does not become elastic until 572°F.
When I bed the barrel I snip a piece of .001 or .0015 shim stock to fit, and cut it down bit by bit until I'm able to very snugly bed the barrel. This keeps me from having to put loctite in there, which I have done and I had some issues with and had to use torch to burn it off to clean it out and redo it again without the loctite.
God is good!!!!!!
I recently installed a Midwest Industries free float quad rail handguard on my Bushmaster MOE 5.56 carbine. I already had a low profile Yankee Hill gas block that just fit under my new handguard. I noticed that after I removed the oribinal barrel nut assembly that the barrel wouldn't budge. I couldn't get it out of the receiver. I didn't really try since I wasn't changing the barrel, but why would it have been stuck in the upper receiver like that?
Might be heat fitted
I'd like to see the range results
I'm no gunsmith nor do I pretend to be but I've got the targets to prove this method works. I'm now mounting all my barrels with green locktite and when I can fit it, .001 shim stock.
Yes, you can still remove the barrel with a LITTLE heat. No need to get out the cutting torch. The little blue bottle from the hardware store works perfectly. Again, use as little heat as possible to remove the barrel.
Your also suppose to season the nut by tightening it and then losing it 3 to 4 times before your final torque value . But good job lapping
It will not affect head space and you should do it vertically so the lapping tool rides flat. I would check and find the slop. Probably a bad upper. Discard it. I would never locktite
@@carlosmartin3587 , yes, I lightly lap the finish off the upper always. But if a upper had that much slop in it I would discard it. I beleive(without rewatching) the video stated dont lap to much or it could effect headspace, which is incorrect. The upper has nothing to do with it. The bolt slams home/into battery and headspace is from bolt face to datum line. So removing material from the front of the upper threading just moves the gas tube back a few .001. My main point was lap the upper in a vertical position so the tool rides flat, which is squarer to the bore line. Doing it horizontally I noticed the tool canting downward.
Head spacing is already determined from bolt and barrel lockup. NOT the receiver trimmed back. You "might have feeding issues if ramp cuts in receiver does not match up to barrel. But headspace IS NOT SCREWED UP JUST BY LAPPING
I take it that making sure the barrel surfaces and barrel nut surface are flat is not as important. Probably because they're steel and likely machined better?
That is a lot of movement. I have done quite a few builds for myself and friends and I have never run into that kind of slop. Always super tight fit. On another note, I doubt its even an issue when barrel nut is torqued. Only thing i ever put on there is aeroshell. Good tip on torque wrench and adapter being at 90 DEGREES. The only thing i would recommend is that after torquing the barrel nut, break it and torque again to account for any thread deformities or foreign material in threads. Now for my personal 2 cents: I have an accurate AR in .308 (1/2'' groups @100). Great rifle. Most of my modern rifles achieve 1'' groups or less. I will take 2'' MOA all day out of an ar-15 though. Better platforms for precision rifles and i consider 1'' moa or less a precision rifle.
When you inserted the barrel into the upper you should've turned it back and forth to evenly distribute the 620 between the barrel and receiver. . . .You also only faced off the receiver so it has 50% contact which also isn't ideal . . .I want over 75% contact surface whenever I lap anything, 90% is even better, 100% the best. . .
or buy a quality upper. I have never once seen a barrel fit into an upper with so much free movement.
John Hellmann
Beyond that he didn't even bother to demonstrate how much it moved with a barrel nut torqued down on it.
This is the issue here, barrel or upper is out of spec.... this is a backwoods fix more than it is proper gunsmith advice. Don't even need to be a quality upper, i have a $40 beer creek upper and a aero precision upper that were both cheap as i could find at the time and had zero issues like that. Hell i had to tap my barrel in on the last one....
Agreed. That's a lot of slop and I don't think he read the specs for Loctite 620. It is good up to .008" - he might have had more than that. Kind of a hack job....
I think his barrel is out of spec. The lapping tool appeared to fit firmly and had no visible wobble like his barrel did. He noted he had to lube it to get it in smoothly.
@@coolkid6364 Just be aware that a tight receiver to barrel extension fitment alone doesn't mean that they are mating properly. You can very well have a "stacking" of high points on both components that are leading to what can feel like a tight fit. Loctite to fill in the "voids" as it were is still a good idea, and it's been demonstrated time and time again to to have a measurable impact on accuracy. There's good information on this on the SOTAR FB group if you're interested in a more technical deep dive into this platform.
For the best accuracy the barrel must not move at all when attached to the upper. Having only a true upper face will not prevent the barrel from moving. With two very flat mating surfaces the barrel can still move around in a circle. Granted, very small amount of movement. To remove the ability to move around you need a retaining compound or an interference fit. The LocTite 620 is only good up to 200C(392F) so it may not be the right choice for a barrel that will get very hot, I guess that depends on how you'll shoot it. Interference fit is really the best way to "lock" the barrel to the upper.
If you are not in competition then most likely none of this really means much. If you are a super critical hobby shooter then lapping should suffice. If you want to bond the extension into the upper, Extreme Heat JB Weld would be better than the 620.
If I wanted to do this for accuracy holding I would get interference fit upper and the lap it true. Heat upper (oven, etc) and chill the barrel extension end in ice water. The sec just before install wipe the extension with full synthetic motor oil then wipe again with dry lint free cloth, this oil will to some extent fill tiny pores and stay there helping to remove mating dead space between upper and barrel. One key step is immediately after mating the two pieces is to get a barrel nut on there and torque it to spec. Let it come back to room temp then redo the barrel nut stuff, etc.
And to note, you can make Aeroshell grease with simple Lucas lithium and some Moly powder. But, any lube/grease on the upper threads is better than nothing at all.
Is aeroshell 64 grease just as good as synthetic motor oil for the barrel extension?
@@grammatoncleric550 "0" weight SYNTHETIC motor oil is the preferred lube for all weather (especially sub zero) as its viscosity never changes and it stays where you put it.
In the past, even that red auto trans fluid was directly marketed as a wonder lube for guns. It failed because it evaporates over time.
Marine-Tex is better at more than 500C. Also a lot less shrink, and more impervious to chemical decomposition making it a great choice for galvonic prevention.
Did you inspect the upper to confirm that the face was not perpendicular to the bore prior to lapping? It might not have needed it and you could’ve lapped it out, a hand tool will not work as good as the cnc that machined that face
That barrel looks like a Century arms set up. I purchased a FAL years ago,thank god i didnt shoot the pos. The barrel was loooosssseee as could be when i took it out to clean it.Took it to mY GS and he showed me the washer they used to repair set back THANK God for DS arms front end . C.I.ARMS told me to piss off.
I beded my barrel with jb wield . torc it to 80 lbs much tighter fit solid!
Sounds like Drath Vader breathing.
hahahaha I agree
Darth. But yeah, it's disgusting....
No kidding? More cardio dude!!
🤣🤣🤣🤣🤣
FWIW, lapping the front of the receiver is only going to get you part of the way there. That's a really loose fit. You need to add shim stock or get a custom barrel extension from BAT that's oversized the correct amount to fit your upper. You may not expect 1/4 MOA, but if your using a single round sled, an AR is capable of it. If you're ripping rounds out of a loaded mag, 1/2 MOA is pretty good in my book.
Is this the new Red and Green show?
Didn't know the barrels could be that loose. My CMMG barrel into a Viltor upper required persuasion to mate up.
Remember guys, do not torque without a lubricant on the threads! Without it.... is not a true torque
Gotta loosen it a tighten again
Works every time
Torque then loosen 2-3 times before final torque. Use GMD Or some type of molybdenum grease like aero shell on the threads. You also want at least 40 to 65 pounds of torque or all of this bedding doesn't benefit you at all.
I agree to use lubrication, but some torque specs are called out to be dry and some to be wet. Depends on the application.
@@timothymickal8172 - Torque and loosen 2-3 times before final torque is only a "must do" when the receiver, or barrel nut, or both are brand new. Once it's been done once you don't have to do it again - the threads don't get any more seasoned. And judging by the wrench marks on the nut, those components were both well used.
Is broken charging handles a symptom of the barrel or headspace not being correct?
Quality barrel and quality upper will fit correctly, have very little play and, when the barrel nut is torqued down, prevent any movement. Ammo and barrel have an effect on the accuracy far more than any lapping.
jhalscott By the look of it this gunsmith has obviously never installed a barrel into a BCM upper!
BigBoyJr76 I remember my first. It was a BA Hanson into a BCM4 upper. Holy... tightness.
Good inside video!! But why green loctite?? That’s new to me...
That barrel extension should be snug or tight fit in the upper receiver if precision accuracy is the goal.
You should measure to see if the hole of the receiver is oversized or the barrel extension is under sized and replace the out of spec part.
Or you can shim it with a feeler gauge set using the thickness for your need. Folding the shim around the barrel extension.
Cheap solution! (GearWrench Feeler Gauge size 32)
This is a nice tip though, thanks for sharing.
It should improve accuracy by supporting the under sized barrel extension all around it. 😉👍🏼
where can I find specs on barrel extension diameter and inside receiver diameter?
How about ceramic paste for assembly?
I guess there won't be a video on how to remove that barrel?
If your barrel wiggles in the receiver then you need a different receiver, a higher quality one. If tge tolerances are off in tge front, then they are most likely off over the entire receiver. A good quality upper, lower, and barrel will provide better results that bedding will.
Only thing I can add is why not place the upper in the vise vertical while you're lapping the face ? Let gravity work for you. The pressure you were applying to the lapping tool plus the torque to make it turn is cocking the tool as much as it would go and is probably why it only surfaced the lower left of the receiver. I'm not expert but I have worked with machine shop practices and built a few ARs in my time. Take it for what it's worth . Just friendly advice .
Thank you, I will try it that way on my next build and see how it works. That is why we make these videos, to share tips and tricks of the trade. Stay safe out there
It removed part of the anodizing because the milling of the threading wasn't true or the thickness of the anodizing was not uniform. Not because of torque on the tool.
@@cleatussfmo7437 ; OK...…?
You can tell by the blemishes on the insert that this technique is long overdue.
I like to do thermal fit barrels and uppers.
I have found that some uppers i put together need like 20 something clicks of adjustment on the rear sight to get zeroed while some require a handful of clicks. I assume lapping the upper would square up the fit and result in less windage adjustment on the rear sight. Does anyone have experience with this problem?
I have heard this along with fitting gas tube and floating a bolt carrier and fine headspacing a bolt can produce .25-.5 MOA grouping from premium barrels like criterions and Noveskes.
i recommend you use a sharpie and color it and do 1 rotation and see if it removed. and no the headspace is off the bolt
nothing like dried up crusty loctite to bed a barrel. darwin award!
Great video... Thanks for sharing.... Love all the critics.... People like "MC" make life exhausting... From one veteran to another I have found that those who feel compelled to go out of their way to "immortalize" themselves usually possess less than half the shit they want you to believe they know!!!
Thank you...happy shooting!
Great info, have you ever removed and barrel that you that bedded with the Loc-tite 620? If so how did you do it?
If you want to increase accuracy spend about an extra $100 and get a VLTOR MUR upper. Did you see the way that Barrel just slides right into the upper without any resistance? I have assembled two different builds with this receiver and in both instances I had to take a board and a hammer and tap it in because it was so snug. That is the key to having a good Barrel install without movement. Also this is an aerospace company and they have very precise Machining plus the receiver is done with extra metal in critical places so it is more rigid, it weighs more than a mil spec receiver even though it is a forged receiver not Billet. I'm telling you if you want to build an accurized rifle this is the receiver to get and you don't have to deal with any of this nonsense with lapping and putting thread Locker on the barrel. All you need to do is put either Molly grease or some anti-seize and tap it together and torque it down. I have been using the moly grease, but I've heard good things about some certain anti-seize compound. The VLTOR receiver is about $160 to $170. You can get one without forward assist for a little cheaper but I always got the forward assist..
There is also no rough sound when you work the action with this receiver, it is smooth as silk right out of the box. There is a reason this receiver costs more money and honestly the price is not astronomical or anything.
Sounds like a Les Paul /Marshall great vid!
Thanks For The Video I’m Building My First AR10 So Will Be Helpful
If your trying to go a little more advanced I actually measure the freeplay then use shim stock to fit extension
Thats my idea! If i can fit it in then why not.
Very good instructions
Why didn’t you use any anti-seize grease?
Is this the problem with a lot of Mossberg Patriot rifles?
Can you remove a loctite bedded barrel without harming the upper? I’ve read you can use a lot of heat but wouldn’t that screw with the aluminum tempering?
Yes, I use a heat gun (no torch needed). I just did one today, a couple minutes with a heat gun and it came right out. The right Loctite to use is 620. It's a bearing retaining compound. As Loctite says, "LOCTITE® 620 is a retaining compound designed for the bonding of cylindrical fitting parts."
@@jbmillard yeah, I’m just concerned with the high heat on aluminum hardening it further and making it more fragile
the heat required to remove the bedded barrel will not harm the upper at all.......@@JP-vx2sr
I think the loctite is silly, but truing the surfaces sure can't hurt.
Im sorry im very new to all the building and painting parts of an AR15 so when i ask why you didnt show us an comparison of the play ,after you lapped the upper ,dont get upset?You wiggled it and showed us teh play yet you didnt, show us the play after the fact? Just curious???
Use a couple drops here, squeezes a 1/4 bottle