AR15 barrel torque

[akjunkie]

Installed a barrel today. I used a Snap On torque wrench. Torqued my barrel to the minimum 30 Ft. Lbs

I assumed the barrel nut "teeth" wouldnt line up with the gas tube hole like my other barrel installs and that I would have to torque the barrel nut some more to line up to the next "teeth".

But today (on this particular barrel install) the barrel nut "teeth" lined up perfectly with the gas tube hole at 30FT Lbs. I went ahead and finished assembling my upper.

Now I'm second guessing myself. Should I have attempted to torque my barrel nut to the next "teeth"? Would that have Exceeded 80Ft Lbs??

[a308garand]

You are fine.
The minimum torque works well.

Now to make you second guess yourself....
-Did you use a dab of grease on the barrel threads? Will help prevent the parts from galling or seizing when the next guy removes the barrel.

-Did you try to tighten the barrel nut, then loosen it, repeating this three times, before final torque? This will ensure the threads have been mated so you get a good torque reading on the final try at getting it tight.

- Did you align the gas tube when the final torque was set? Ensuring the gas tube was not leaning left/right on the barrel nut and that it fits into the upper receiver, centered into the receiver hole for the gas tube.



ps,
"Should I have attempted to torque my barrel nut to the next "teeth"? Would that have Exceeded 80Ft Lbs??"

If you want to torque it farther than the minimum,,,tight/loose/tight/loose with the barrel nut to get it closer to the next notch. This will get a difficult barrel nut almost aligned before you go for the final try at 30-80....So if you want a bit more than 30, you may get a bunch closer to 80 just trying to get to that next notch. The barrel will not loosen over time if you installed it correctly, even if you went with the minimum torque. You are fine.

[akjunkie]

You are fine.
The minimum torque works well.

Now to make you second guess yourself....
-Did you use a dab of grease on the barrel threads? Will help prevent the parts from galling or seizing when the next guy removes the barrel.

-Did you try to tighten the barrel nut, then loosen it, repeating this three times, before final torque? This will ensure the threads have been mated so you get a good torque reading on the final try at getting it tight.

- Did you align the gas tube when the final torque was set? Ensuring the gas tube was not leaning left/right on the barrel nut and that it fits into the upper receiver, centered into the receiver hole for the gas tube.



ps,
"Should I have attempted to torque my barrel nut to the next "teeth"? Would that have Exceeded 80Ft Lbs??"

If you want to torque it farther than the minimum,,,tight/loose/tight/loose with the barrel nut to get it closer to the next notch. This will get a difficult barrel nut almost aligned before you go for the final try at 30-80....So if you want a bit more than 30, you may get a bunch closer to 80 just trying to get to that next notch. The barrel will not loosen over time if you installed it correctly, even if you went with the minimum torque. You are fine.

Well, had time to kill tonite.

Knocked out gas tube and reinstalled barrel again.
Loosened/retightened 3x with 1/2 in breaker bar.
Torqued to 40lbs and the barrel nut teeth went pass the alignment hole.
Tried torquing the nut down to the next teeth and my wrench kept slipping off. Might've chipped one teeth of the barrel nut.
Loosened and retorqued to previous 30Ft Lbs. I gave my torque wrench a little xtra pull once it "clicked" at 30. "Teeth" and "hole" lined up like before and continued with rest upper assembly. And yes, had some white lithium grease on the threads.

Just occured to me the gas tube itself would keep the barrel nut from backing out.

anyways, thanks for your help.