Posted: 11/23/2016 1:05:55 PM EDT
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I just got my WOA barrel in from adco yesterday. It was the last piece I was waiting to do my first precision AR build. Shooting for <1 moa (Don't need 1/2 moa, but would be super stoked to have 3/14-1 moa). I have a stripped aero precision upper. I was hoping the barrel extension fit would be snug and maybe even require some force but it slides in fairly easily and has a tiny bit of wobble (before you tighten of course).
For you precision builders out there, am I screwed? Should I scrap this upper and try to get another one like maybe a BCM designed for a tight fit? Was really stoked to build this thing but maybe I should wait and get a different upper. Should I bed the extension in loctite or something to fill the tiny gap and add extra rigidity to the system? Its not a ton of wobble, just a tiny bit, but again I've heard a real snug fit is best for accuracy. |
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It will shoot fine as is, millions of rifles have been built without bedding or shimming the barrel extension.
I have used Loctite 609 and 620 as well as Devcon steel epoxy to fill upper receiver/barrel extension gaps. One thing for sure, I won't be re-barreling those upper receivers when the barrel is toast. You will play hell getting it apart. You can use shim stock wrapped around the barrel extension to fill the gap. Several YouTube videos show multiple techniques using all of these methods. |
| Ok I'm thinking about bedding it in blue 242 just for the heck of it and for the peace of mind haha. Would that work ok? I know it breaks down temp wise sooner but I read people having shot thousands of rounds and never had an issue with it. Also supposedly if it breaks down it just turns to powder and still takes up the space as a filler. |
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Take a look at Hellbender's guide. Good info, and simple to do. Myself personally, I wouldn't bed it with loctite - if it's really loose, there's no way to guarantee it will be straight from the get go, AND continue to stay that way over time as the barrel and upper goes through several heat cycles. Hellbender's way is a guaranteed good fit that will stay that way over time, and without much extra work than using loctite. Just my opinion. http://www.ar15.com/forums/t_16_4/42_Hellbenders_guides_to_Ultimate_AR15_and_or_AR10.html |
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609 and 620 are specifically designed to fill gaps in cylindrical slip fit parts. I think the 620 can withstand heat up to 450F. Make sure you put it only on the barrel extension, never inside the upper. This will insure any excess flows out of the upper instead of into the upper.
After inserting the barrel I wipe any excess off, grease the receiver threads and snug the barrel nut. I store the rifle muzzle down for at least 24 hours to allow the Loctite to set. |
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Quoted:
I would use at least rocksett over locktite due to temperatures. The ones mentioned above should work too. Came to say this. I've never done any barrel/receiver bedding, and never had much need to try it. But if I did, I'd use rocksett over loctite. It may never get hot enough for the loctite to loosen, but it certainly won't get hot enough for the rocksett to loosen. |
| Ok well thanks everyone for your thoughts. I'm thinking I probably have been over thinking this but I don't know. I'm now leaning towards bedding it with nothing and shooting it. If I get in the 3/4-1 moa range I'll be a happy camper. If I don't then bummer, I'll have to start experimenting and loctite or rocksett or steel shims will probably be in order. |
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Groups size will be dependent on bullet quality. FMJ's (M193 or M855) ammo is lowest common denominator, they rarely shoot well from any rifle. I find 52/53 grain match bullets shoot the tightest groups at 100 yards regardless of barrel twist rates. Those little bullets are amazing on target even when fired from rack grade chrome lined barrels.
Good Luck. |
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Quoted:
Groups size will be dependent on bullet quality. FMJ's (M193 or M855) ammo is lowest common denominator, they rarely shoot well from any rifle. I find 52/53 grain match bullets shoot the tightest groups at 100 yards regardless of barrel twist rates. Those little bullets are amazing on target even when fired from rack grade chrome lined barrels. Good Luck. Yes I definitely plan on shooting factory match ammo and figuring out which it likes best! Thanks for the recommend on 52/53. I'll give some of those a shot. I also am hoping it shoots 77 gr well for the long distance shooting I want to do. Hoping in the next year to get my own place and start reloading then I can custom taylor the rounds. But for now I'm going to shoot factory match. |