Torqued Barrel Nut

[Whelenon]

OK, I torqued the barrel nut to 80 ft.lb. and it's 1/2 way between tabs.



Now what?

Also, assembly lube, what's the reason not to used the lube w/moly-graphite?

[dmsims21]

I have read that the graphite is conductive, which will allow galvanic corrosion between two dissimilar metals. I guess that if you had an aluminum barrel nut, corrosion would not be an issue.

[Tedward]

I asked my gun smith and he said to torque it till it lines up. After that I read the directions and they said you may have to grind off the barrel nut tab to fit the gas tube in. Mine was a Troy TRX Alpha rail and wish i would have done that rather than torque it so hard. nothing broke but felt way over 80lbs as they call for the max amount.

[cory]

I'm assuming you tried backing it off. What was the torque at then?

[Whelenon]

I asked my gun smith and he said to torque it till it lines up. After that I read the directions and they said you may have to grind off the barrel nut tab to fit the gas tube in. Mine was a Troy TRX Alpha rail and wish i would have done that rather than torque it so hard. nothing broke but felt way over 80lbs as they call for the max amount.

Unfortunately grinding the tab is not an option with the MI Handguard, it indexes off the nut so the rail would not be at 12 o-clock.

[NugginFutz]

This may or may not be obvious, but did you tighten it, back it off and retighten at all? I noticed that this has the effect of allowing the nut to turn further, on each successive retightening. Also, using a thread lube will aid you significantly.

[LRRPF52]

Back off! There are guys who have torqued past 80ft-lbs, and crushed the upper receiver.

The graphite in grease can do this if moisture gets in there, which is unlikely.

The big reason to avoid graphite-based greases for the barrel nut is that graphite is at the far end of the galvanic series (the cathodic end) and could cause both of the metals to corrode. Personal take: when it's in a grease that keeps moisture sealed out it's probably not the end of the world, but it doesn't hurt to avoid it, either.

http://www.m4carbine.net/showthread.php?t=36888

[kiwi 1]

I have a couple of extra barrel nuts that I keep for new barrels so if one does not line up I try another nut.

[Kohoki]

Better use some kind of grease which contains molybdenum disulfide or XF-7

[kamrr4437]

I think its a torqued kind of high if you ask me. I torqued mine to 60 ft lbs and isnt going anywhere and it shoots less than half moa at a hundred yards. I would back it up until it lines up for your gas tube. I wouldnt grind anything. Turning it with a torque wrench is one thing theres alot of leverage there. But try to twist one off with your hand thats even at 30 or 35 lbs, it wont happen. Trust me it will be tight lol.

[sneaky one]

Search the web for bbl. nut shims. A pkg. will have a few of varying thickness. Hope you didn't gall the threads already.

[dmsims21]

Dumb question. Is I on backwards? I thought the tabs should be toward the muzzle end.

[Sojorboy]

I would back it up and line it up with the previous hole. I had a friend try to go to the next hole after 60 lbs, ended up busting the nut and damaging the threads on the receiver. Be very careful, good luck

[Longshot_34]

I've found that if you torque, back it off, torque again, back it off...things index a lot easier. +1 for the 80ft/lb being a bit much.

[frank]

Torque the nut to 40 three times. On the third time line it up on the first opening past 40. If you get to 80 without it lining up, I'd take it completely off and try again. If you get the same results, try a different barrel nut.

[Whelenon]

I backed if off to previous opening. For barrel nut/gas tube alignment it torqued at 35 ft.lb. IMO 35 ft.lb is too light, ya I know I've read 30-40 pounds is enough. I'd be more comfortable with 50-60 ft.lb. I'll get it out and see how it shoots. In the mean time I'm going to order a couple barrel nuts.

Very helpful, thanks guys, once again the Horde rules.

[frank]

Did you flip it around? As dmsims pointed out, if that is a factory barrel nut, it is on backwards in the photo.

[Whelenon]

Did you flip it around? As dmsims pointed out, if that is a factory barrel nut, it is on backwards in the photo.

lol, no, it's on right. It's for a Midwest Ind. Handguard with there proprietary barrel nut.

[joker31]

I use and always have used (even Military weapons) Anti-Seize, It doesn't Bake off like greases and oils, It keeps the threads from galling and it has never been a problem taking it off later. I also agree with the back it off and try again approach, My last build was going the same way and I backed it off and re-torqued it and it lined up perfectly.

[Whelenon]

I use and always have used (even Military weapons) Anti-Seize, It doesn't Bake off like greases and oils, It keeps the threads from galling and it has never been a problem taking it off later. I also agree with the back it off and try again approach, My last build was going the same way and I backed it off and re-torqued it and it lined up perfectly.

I'll give it a try, thanks.