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msweet16
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Posted: 1/13/2009 8:17:34 AM
Some are loctite crazy on ARs especially on duty or comp guns. Barrel nut? I see where grease is recommended. I've done several without grease with no problems.
Also, if you feel like it's torqued about right and there's a bit of a bbl nut tooth in the way, does anyone grind a little off of just one for gas tube clearance? It seems like backing it off that hair to line up makes the setup mentally seem "looser" than you want and tightening it up one more notch seems "too tight".
VA-gunnut
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Posted: 1/13/2009 8:32:24 AM
Um, no loctite and especially no grinding.
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Silent_Knight
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Posted: 1/13/2009 9:50:20 AM
I've never heard of using loktite on barrel nut.
bigbore
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Posted: 1/13/2009 9:54:06 AM
Most of the Noveske uppers I've see were loctited on any and every piece that has threads. Nothing wrong with it, it just makes things PITA for the flavor of the month guys who change their handguards 2 or 3 times a year...
I'm no good at telling people what they want to hear when I dont believe it myself :)
Wizz
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Posted: 1/13/2009 2:54:32 PM
Absolutely nothing wrong w/it and it's a good idea. Just use the Blue loctite and you'll be just fine, it has a relatively easy break strength. Don't use the Red or you'll really have to put some muscle behind it or possibly use a bit of heat.
bcd
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Posted: 1/13/2009 6:23:25 PM
With the amount of heat that builds up around there, would the Locktite even do anything ?
Amish_Bill
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Posted: 1/13/2009 6:38:38 PM
God No!

I have an upper that I picked up used... and I swear whoever had it before used either red loctite or jb weld on the barrel nut. I've tried Kroil, Freezing, Heat, etc, and there's no way that damn nut is moving. Pisses me off, as I need the barrel out of the upper.
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Dan1918A2
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Posted: 1/13/2009 6:55:16 PM
I just use moly grease. So far, so good.
machinehead
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Posted: 1/13/2009 7:22:57 PM
why locktite it. the barrel nut can only go as far as the gastube. there are torque figures there for a reasaon . off the top of my head, 35 min, 80 max. somone will correct me if im wrong. the grease called for is molybdium disulfied grease. i have very rarely had a barrel that would not line up at the 80 max torque. if that happens i put another barrel on. if you overtorque you can get some windage problems by messing up the index pin slot.
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Blacksnake
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Posted: 1/13/2009 7:43:01 PM
Originally Posted By machinehead:
why locktite it. the barrel nut can only go as far as the gastube. there are torque figures there for a reasaon . off the top of my head, 35 min, 80 max. somone will correct me if im wrong. the grease called for is molybdium disulfied grease. i have very rarely had a barrel that would not line up at the 80 max torque. if that happens i put another barrel on. if you overtorque you can get some windage problems by messing up the index pin slot.


+1

30-80ft-lbs with moly grease. You torque 3 times to 30ft-lbs and loosen after each time, then do the final torque until the slot in the nut lines up with the gas tube hole in the upper. 70ft-lbs is the farthest I've had to go with this (not too tight at all, IMO), but I damn sure wouldn't use loctite, loosen it, or grind the barrel nut.

Blacksnake
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Posted: 1/13/2009 7:43:48 PM
Originally Posted By bcd:
With the amount of heat that builds up around there, would the Locktite even do anything ?


Agreed. If you could hear when firing, once it got hot enough you would hear the loctite crackling as its bond breaks. Useless.

bigbore
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Posted: 1/13/2009 8:37:39 PM
Originally Posted By Blacksnake:
Originally Posted By bcd:
With the amount of heat that builds up around there, would the Locktite even do anything ?


Agreed. If you could hear when firing, once it got hot enough you would hear the loctite crackling as its bond breaks. Useless.




most semi auto ARs will not get hot enough to loosen the loctite on a barrel nut. And if it does get soft, it hardens back up once it cools. I've seen enough red loctite on barrel nuts to know it it holds tight. If you want loctite on your barrel nut go ahead, it is not useless.

I'm no good at telling people what they want to hear when I dont believe it myself :)
Blacksnake
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Posted: 1/14/2009 4:51:08 PM
[Last Edit: 1/14/2009 4:54:50 PM by Blacksnake]
Originally Posted By bigbore:
Originally Posted By Blacksnake:
Originally Posted By bcd:
With the amount of heat that builds up around there, would the Locktite even do anything ?


Agreed. If you could hear when firing, once it got hot enough you would hear the loctite crackling as its bond breaks. Useless.




most semi auto ARs will not get hot enough to loosen the loctite on a barrel nut. And if it does get soft, it hardens back up once it cools. I've seen enough red loctite on barrel nuts to know it it holds tight. If you want loctite on your barrel nut go ahead, it is not useless.



Typically used Loctite 262:

300F for 50% strength, 450F or so to break loose. Barrel nut or quad rail is most likely to loosen while firing (twisting, etc.).

Depends on how hard you run your guns, but IMO, no substitute for proper torquing of the barrel nut.

I would certainly not recommend people following proper torquing specs to use it, YMMV.

ETA: I do like my Noveske uppers though, and a couple Young N/M BCG's, loctite and all.