Installing USGI barrel nut to specific torque/shaving any impeding teeth: problem?

[DreadPirateMoyer]

Odd question I have for the hive:

Let's say I was interested in installing a barrel nut to a specific torque value (40-50 lb-ft) for accuracy reasons on a precision build, and I was also interested in using a standard USGI barrel nut because I prefer having standard equipment on all my guns: would there be any mechanical, practical, or otherwise negative consequence to shaving the tooth in the way of the gas tube, should there be one in the way?

I understand this is not even close to the correct method of installation, and I understand the proper range is 30-80 lb-ft. I've removed/installed barrel nuts in the past and never had any problem getting the teeth to align in that torque range, and I use Loctite anti-seize like IG. I completely understand the mil-spec way of doing this. I'm just asking, if one were to seek a very narrow torque range on a precision build, would there be any problem with shaving a tooth off of the barrel nut if one were in the way?

I can't see there actually being a problem with this. I understand the theory is that the gas tube acts as a barrier of last resort to a loose barrel nut, but I won't have that problem and I think that's only an urban legend for barrel nuts improperly installed below the recommended torque range (not to mention it's not good for the gun to have the barrel nut held by the gas tube anyway). I see non-timed barrel nuts like those from Geissele out there in the wild that don't support the gas tube, so I can't see that actually being a valid argument at the end of the day. Otherwise, so long as my free float rail attaches to the barrel nut, is there any problem with removing a tooth so one achieves a specific torque value?

Many thanks for your help. You guys have done this a lot longer than I have, so your advice is always appreciated.

[CoryCop25]

I have seen this done while installing Lancer carbon fiber rails. It does work but it is usually done on gamer rifles not "save your life" rifles. I also believe that you will have some trouble grinding that tooth off because the steel is tougher than the aluminum nut on the Lancer. I have seen and had barrel nuts come loose on me. I had a DD Lite rail that I put together with the same light torque concept as you are thinking about.
If cost is a factor in building your precision set up, then you are going to sacrifice some accuracy by using the GI barrel nut. If it is not a factor, I would suggest using a hand guard like the Geissele with a longer more barrel supporting barrel nut.
Good luck and have fun with your build!

[DreadPirateMoyer]

I have seen this done while installing Lancer carbon fiber rails. It does work but it is usually done on gamer rifles not "save your life" rifles. I also believe that you will have some trouble grinding that tooth off because the steel is tougher than the aluminum nut on the Lancer. I have seen and had barrel nuts come loose on me. I had a DD Lite rail that I put together with the same light torque concept as you are thinking about.
If cost is a factor in building your precision set up, then you are going to sacrifice some accuracy by using the GI barrel nut. If it is not a factor, I would suggest using a hand guard like the Geissele with a longer more barrel supporting barrel nut.
Good luck and have fun with your build!

It would take a bit of work, of course, on a Colt barrel nut, but it would eventually give in with enough work. And on the looseness issue, even if that were to happen, I'm not a fan of the gas tube holding the assembly together anyway.

I would normally go with a Geissele in this situation if I could, but they don't fit Mega billet uppers, unfortunately, which is the upper I'm using on this build. That on top of the fact that I like keeping everything as standard as possible leads me to a USGI barrel nut.

[Clint]

For your needs, I think that using a barrel nut shim would be the way to go.

[Saginaw79]

IDK, Id tighten it to your preference, and then back it off to get alignment, shouldn't have to back off very far.

[CoryCop25]

For your needs, I think that using a barrel nut shim would be the way to go.

Not a fan of shims but for this application, it may be ok.

I would normally go with a Geissele in this situation if I could, but they don't fit Mega billet uppers, unfortunately, which is the upper I'm using on this build.

This may be another option....
I have milled the bottom tabs of the Geissele rail to fit on Billet uppers. Unfortunately, I don't have any pictures. I milled the tabs so it fit on the upper then put shorter anti rotation screws in the existing holes.

[Iraqgunz]

I hope you have never done a barrel like that. You can't tighten or torque something and back it off because it will lose its its torque.

IDK, Id tighten it to your preference, and then back it off to get alignment, shouldn't have to back off very far.

[Iraqgunz]

OP,

You are over thinking this. Also, where or who provided you with this so called torque value and made you think that this was the optimal value?

I would venture to guess that many of the barrel nuts I have done were in that 40-50 ft./lb. range already.

[Serpico1985]

Not the OP but FYI Grant recommends torquing to the lower weight within spec for accuracy (with barrel nuts and muzzle devices). The Geissele rails recommend 40 foot pounds (since there is no timing needed with their lock up design). The Centurion CMR rail specifies 30 foot pounds (again no timing needed).

So again not being the OP I could see why/how he would have this idea. If we all agree that if the barrel nut is installed properly it should not work itself loose then relying on the gas tube to keep it in place, the what would be the harm in doing his method?

[Saginaw79]

I hope you have never done a barrel like that. You can't tighten or torque something and back it off because it will lose its its torque.

I was told to tighten it down three times(tight back off, tight back off, tight) and if they don't align, you slightly back off it until you get the clearance for the gas tube. Since then I haven't even built mine just buy uppers already assembled for the most pat. Now I will seek other knowledge before I do it