AR-15 Barrel Nut Question

[WhyteP38]

I'm installing a barrel to my upper, and I'm running into a problem.

When I tighten the barrel nut, the wave washer and snap ring get out of alignment with the gas tube hole. By using a small piece of rod, I can wiggle the wash washer into alignment, but moving the snap ring is a no-go. I expected some difficulty in keeping things aligned, so before installation I lubed the groove where the snap ring goes, but the snap ring won't budge.

What's the trick behind getting everything lined up?

Thanks!

 

[DnPRK]

Push on the end open end of the c-clip with a punch. Don't be gentle. It will slide around the groove.
c-clip -> C\ <- punch

 

[MisterPX]

Tkae the c-clip loose, so there's no tension on the delta ring spring. Torque your nut, then install the spring and c-clip.

 

[USMCG_HMX1]

Do NOT overtighten the barrel nut or you'll warp the barrel index pin and end up with a major windage problem later on.




Kris

 

[WhyteP38]

Good info; thanks.

I have my torque wrench ready, I know to put anti-seize on the threads and do the "3 times tighten to 30-foot-pounds, then start at 35-foot-pounds" drill, and I've heard you don't want to go past 80-foot-pounds. That 80 part makes me wonder. Is that number real or folklore? 80-foot-pounds sounds like a lot for a steel nut on an aluminum thread.

 

[44 AMP]

Never heard of 80 ft/lb

1977, M16A1, GI specs were to torque to 35-40 ft/lb and then tighten to line up barrel nut for gas tube. And that is what we did, as I recall. Bolt carrier key screws were torqued to 35-40 inch/lbs, and then staked. Buffer tube was, I think about 35 ft/lbs. Been a long time, I may be a little off on the numbers, but I do not recall 80 ft/lbs on anything on the M16

 

[SSN_Doc]

The 80 ft/lbs is a "do not exceed" limit.

Torque to 30 ft/lbs, back the nut off, repeat to 30 ft/lbs, back off once again and torque to 30-35 ft/lbs and then proceed to tighten until the gas tube notch is aligned, but do not exceed 80 ft/lbs.