01-03-2020, 04:01 PM
bbqncigars Wrote:I highly advise the use of a Magpul Bevblock when torquing a barrel nut or such. It's a nice multipurpose tool that mates up to the locking lug recesses to keep stress off of the upper receiver.
I have one.
Without typing a book (and remembering that a picture is worth a thousand words), I did not want to use the locking lugs to torque against. Alexander Arms said I needed to tighten the barrel to the extension with 120 lb ft of torque. I REALLY, REALLY, REALLY don't think it would've been a good idea to use the lugs to resist that force. (Lugs are part of the extension: the barrel had to be tightened onto the extension.)
I cannot emphasize how easily the barrel came out of the extension.
When I put this together, I used the same techniques I've used on my other AR builds.
I'm happy to take the blame for any and all "oddities". But, the fact remains, rounds were hard-stuck in the chamber, repeatedly. This did not stop until I polished the chamber. (I did not borescope it.) When I unscrewed the muzzle brake, I was surprised that I had to use the force I did. It took ~20-30 lb ft. BEFORE the muzzle brake loosened, the barrel spun out of the extension.