.308 barrel nut torque questsion

[CANNONMAN]

I've got an AR10 .308 and when putting on the barrel nut I'm way of for alignment of the gas tube. If I align it to initially fit, I only get about 20 #'s of torque. If I put all the shims on that it came with I'm pretty far from alignment. I think I want between 35#'s to 90#'s but I am hesitant about seeing if the nut will spin up to alignment with that much pressure. I'm I just being skittish and see or should I put a few more shims on? I see that some say to torque the nut several time to it's alignment as long as it's within the parameters above. True? Is there a thing as too many shims? Thanks for helping me with my first shimming experience.

 

[Blue68f100]

There should be several locations for the gas tube to go through. I like pulling a little anti-size compound on the threads and torque it several times to around 50-75 ft/lbs. On the final torque see how much rotation is needed for alignment then use appropriate shims. Some mfg don't use them. My friend called the mfg after normal procedures did not work. They said they keep torquing till they align up. Bad on overloading the base material. Once we found that out I made a special tool to fit the barrel nut so we could apply more torque. It was so tight I had to use barrel clamp w/resin and 36" pipe wrench on a barrel nut wrench. Action wrench backing the barrel, to protect the upper housing. Estimated torque was over 150 ft/lbs. The reason a big pipe wrench was used.

Normally the supplied shims work provided they gave you a complete set with different thickness.

 

[CANNONMAN]

Thanks Blue. There are 4 positions and I fear I'd need similar torque as you used. I have all the shims on and I'm less than half the distance to the first alignment. This would be about 50 degrees off alignment. That's by considering 90 degrees to each alignment. Without shims I'm aligned by about 20#. Well, thanks Blue I appreciate you.

 

[Blue68f100]

Measure your shims, there should be 2-3 different thickness.

 

[mtrmn]

Torque it to your desired torque, mark the place where the gas tube needs to go, remove the nut, and use a dremel or small chain saw file to cut your own notch for the gas tube.