How important is it to use a toque wrench when installing an AR barrel?
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Tighten the barrel nut to 35 ft lbs, then loosen and tighten twice more. On the third time after you have mated the receiver threads to the barrel nut, hit the 35 ft lbs, then without going over 80 ft lbs, tighten the nut past the 35Ft lbs to index the top two nut spines to allow the gas tube to pass through them without binding.
Not needed
It is almost always necessary to go over the recommended torque value to line up the gas tube anyway.
Do you have a vice block and barrel wrench?
Use some moly grease on the threads, tighten it in all the way, back it out, send it in again until its tight, then go a bit more to line up the gas tube.
I had to google the torque value, and this is what I remember reading a while back
Not needed
It is almost always necessary to go over the recommended torque value to line up the gas tube anyway.
Do you have a vice block and barrel wrench?
Use some moly grease on the threads, tighten it in all the way, back it out, send it in again until its tight, then go a bit more to line up the gas tube.
I had to google the torque value, and this is what I remember reading a while back
I believe the recommend range is 30-80 ft lbs. Are you saying you have to go over 80 to line up the tube?It is almost always necessary to go over the recommended torque value to line up the gas tube anyway.
I believe the recommend range is 30-80 ft lbs. Are you saying you have to go over 80 to line up the tube?
Agreed. I've done multiple builds without grease or a torque wrench and never had a problem. The last build, a .308 LR, I figured I'd throw some grease on and torque it to specs. This thing went from -30lbs to well over 100lbs between notches. I chalked it up to excess grease but man that one was a bitch.Many searches show 35lbs barrel nut torque without describing the method.
(I meant it is necessary to go over this value)
If actually using a torque wrench the proper method would be something like this:
Torque to 30lbs, fully loosen.
Torque to 30lbs, fully loosen again.
Torque to minimum 35lbs, if gas tube does not line up, continue without exceeding 80lbs until gas tube lines up.
35-80lbs is a very broad range. The anodizing in the upper receiver, the phosphate of the barrel nut, the type and amount of grease used on the threads (or lack of! ) will all vary the degrees of rotation of the nut between 35-80lbs.