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AR15.COM
4/6/2026 10:23:23 PM EDT
Has anyone had to use a shim with a LaRue barrel nut. Was trying to tighten one today but it just wouldn’t line up. If you did, what is a good source for buying some?
Carpe diem - Seize the day
Carpe per diem - Seize the expense check
4/6/2026 11:35:57 PM EDT
[#1]
I don't have any Larue barrels. You can get shims at Bison Armory.
4/7/2026 12:01:34 AM EDT
[Last Edit: mettee][Edited] [#2]
What is your minimum torque to line up a hole, and how much would it take to make it to the next hole?

What grease is on the nut, and is it on the flange of the barrel extension?
4/7/2026 12:31:09 AM EDT
[#3]
At hand tight it’s almost there. At about 15 to 20 foot pounds it’s lined up. 30 foot pounds is too much. It’s not going to be possible to get to the next hole without breaking something.
Carpe diem - Seize the day
Carpe per diem - Seize the expense check
4/7/2026 2:00:21 AM EDT
[#4]
Each turn is about 55 thou. Probably 1-3k of shims should do it.
4/8/2026 5:39:13 AM EDT
[#5]
Quote History
Originally Posted By RV8guy:
At hand tight it’s almost there. At about 15 to 20 foot pounds it’s lined up. 30 foot pounds is too much. It’s not going to be possible to get to the next hole without breaking something.
View Quote


Any grease? I use the borwnells action lube plus, its got moly.

30 isnt too much, over 50 is too much in my opinion. Use grease, tighten and loosen three times. Then try again in progressive numbers.

If you arent using an action rod(assuming you are), you should be.
4/8/2026 6:31:23 AM EDT
[#6]
I'm not sure what the larue barrel nut torque spec is.

But the original m4/m16 barrel nut can be torqued from 30-80 ft lbs for alignment.

I've went to 80 before. It was fine.
4/8/2026 7:33:33 AM EDT
[#7]
Quote History
Originally Posted By mettee:


Any grease? I use the borwnells action lube plus, its got moly.

30 isnt too much, over 50 is too much in my opinion. Use grease, tighten and loosen three times. Then try again in progressive numbers.

If you arent using an action rod(assuming you are), you should be.
View Quote

Yes, there is grease.

By 30 being too much I mean it turns the nut too far to line up. I’ve taken the torque all the way up to 70 and the situation never really improves.

Carpe diem - Seize the day
Carpe per diem - Seize the expense check
4/8/2026 6:01:32 PM EDT
[#8]
Run it at 20 and see how it does. I’ve seen them that low before some like it, some don’t. Shimming so you line up between 30-50 is better.
4/8/2026 8:12:48 PM EDT
[#9]
Ive never used or needed a shim. It just seems strange that you get to 70 ft lbs and the next hole won't line up.
4/18/2026 3:20:42 PM EDT
[#10]
Got the upper put back together today. Two shims , 50 ft/lbs and the barrel nut was right on the money.
Carpe diem - Seize the day
Carpe per diem - Seize the expense check

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