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Discussion Starter · #1 · (Edited)
Greetings, I'm sure this has been discussed before but I'll ask it anyway. I'm going to install a 20" barrel on an AR-15 A1 upper. It's been a lot of years since I've installed a barrel. I've watched the Brownells video, they say keep it close to 30 ftlbs then I read one post where 90 ftlbs was mentioned . When I was in the Navy and was replacing worn out Vietnam era M-16 barrels we torqued the new ones to 70 ftlbs + or - per NAVSEA. I have 1 AR-15A1 I built back in the late 80's and torqued it to 70 ftlbs as I did in the Navy . I've put a LOT of rounds thru it with no issues at all. Now I'm just old and confused LOL... So what IS the correct torque ??? ANY help most appreciated !!
 

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The way I was taught is to torque it loosen it and torque it again three times to 30 pounds. Then check your gas tube hole alignment and torque it some more, if necessary, up to 80 lbs. to align the gas tube holes. If you have to go to 80 lbs. and they still don't line up, you will have to loosen and retorque it several times until it does. I had to do this on mine and it hasn't caused any problems. Don't forget to lube the threads.

I got this information straight from the Army/Air Force manual TM 9-1005-319-23&P dated Sep. 2001. Its on page 3-41 and 3-43.
 

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IIRC, the AGI AR building dvd suggested something like 35 - 90 ftlbs. Ole Bob Dunlap recommended taking it up to near the max, and backing off until it lines up right. I don't go all the way to the max with worn in and oiled threads. FWIW I took the barrel nut off my factory RRA midlegnth carbine, and it was barely 35 ftlbs. It had about 2,000 rounds through it when I removed the barrel nut to install a floating handguard tube.
 

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Both Answers above are dead on according to military specs.
I've heard that some of the new parts can have a widened slot on the reciever where the "pin" on the barrel aligns to prevent canting. As an Armorer, I had rebarreled 100's of m16a2's and I have never seen one loose enought to cause canting but reliable sources tell me some of the new kits have this problem (OK, new to me is 15 years).

To this day I still have a perfectly calibrated left arm. I can tell torque +- 5lbs form 30 to 80 lbs

PS
Are you using one of those new fangled barrel wrenches or the old school 3 pronged wrenches.
 

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Discussion Starter · #5 ·
Thanks for all the advice guys. Dix, I'm using the same tool I used back in '81, so yes old school 3 prong wrench, also using an older A1 upper with a new GI 20" A1 barrel . I have the barrel and the barrel pin fits tight in the receiver slot. just waiting on a new delta ring and gas tube .
 

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Discussion Starter · #6 ·
Thanks guys for the help . Parts came this afternoon , ended up going to 35ftlb's. Everything lined up, YH gas tube in, new MAGPUL MOE hand guards on. Easiest re-barrel i've ever done, bout 30 min's. Took it outside put a 30 rd mag thru it NO problems at all . Thanks again :thumbsup:
 
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