AR Barrel nut tension?

[Littleton Shot Maker]

does the barrel nut on the Ar 308 use same tension foot pounds as the ar 556 platform...?

I am not armorer and can not find what foot pounds to torque barrel nut to...for 308, am I missing something?? Or over thinking the whole thing??

''building'' up my first ever lower and upper combo- don't want to get hurt!!

just another evolution in the owning and shooting of the Ar platform- being able to fix, build or repair these weapons systems will be increasing importnat to me and many other I suspect very soon, and I know I am behind the curve

[M-Tecs]

The recommended torque on the AR-15 is minimum 35 ft lbs on and 80 ft lbs being the max.

The recommended torque on the AR-10 is minimum 45 ft lbs on and 90 ft lbs being the max.

The reality for both is torgue to about 60 to 75 ft lbs three times to seat the threads than the fourth time torque to contact and than go to next gas tube alignment hole. Some of the AR10 barrel nuts don't have aligment holes so 60 ft lbs is enough. Some blue Loctite and some use anti-seize. I have used both and none have ever came loose. Loose is not dangerous but it is h**l on accuracy.

[Littleton Shot Maker]

thank you, NOW to learn how to use a torque wrench......JOKING guys don't get too serious...
I had read it some where a long time back but never took it to heart as I thought I would never BUILD my own back then.

wow we can't use the word heel?? what is going on ?? did I step into a twilight episode --- aren;t we grown ups here?
Most of us any way ...sure some one will set me straight again soon.

M-Tecs, thank you yet again for your help , should have just asked 'you' earlier when we where "talking". I am certified trigger puller not fixer, so I now have to learn a new skill to pass on to the Girls.
YES I am working with my kids to get them trained up from the bottom up. shoot em , fix em, and reload for em....
I won't be around for ever and it's MY job to start them off RIGHT!!!

[dkf]

Milspec is to use Aeroshell 33 grease on the threads of the upper before torquing the nut. I use a lithium complex grease I keep on hand.

[6bg6ga]

I don't think the receiver and nut if aluminum are going to take 35-80 ft lbs of torque.

[M-Tecs]

I don't think the receiver and nut if aluminum are going to take 35-80 ft lbs of torque.

I guess we are all wrong.

http://shop.ar15sport.ihoststores.com/custom_v3.aspx?id=3

http://blog.adamsarms.net/blog/ar-15-barrel-installation

http://www.thehighroad.org/archive/index.php/t-544371.html

http://forum.308ar.com/topic/4399-what-is-max-torque-for-barrel-nuts/

http://www.ar15.com/mobile/topic.html?b=3&f=4&t=315921

http://www.65grendel.com/forum/showthread.php?3406-Barrel-nut-Torque

[GabbyM]

I don't think the receiver and nut if aluminum are going to take 35-80 ft lbs of torque.

The 80 ft lbs max seams right as I'd expect threads to be pulled out of time somewhere in there. I'm sure it's been tested thousands of times.

As a retired machinist. I've machined some 7075 alloy aluminum. It is some seriously tough metal. Will make a twenty horse power cnc mill shake just taking light cuts. We are not talking beer cans here.

[6bg6ga]

The reason I questioned this is the info for my rail and barrel nut say do not exceed 30 ft lbs. Now, I don't question that the receiver will take the torque but I do question if my Monstrum barrel nut will.

[6bg6ga]

Since I still cannot edit ..... another post.

Info on my Monstrum rail says 6061 material but no mention on the barrel nut alloy. Thus my question.

[KCSO]

The most important thing is to get the barrel nut aligned at under 80 fp. I use lithium grease and will start clocking in the nut at 40 pounds and then try and get it to the next hole. 40-60 pounds will never come loose on you. Always use a receiver block and filler when torqueing.

[Littleton Shot Maker]

receiver block on order,BUT A Filler??
Sorry I am slow, we are talking about the 'plastic' block that has 2 pin holes and fills the mag well right?? So I can lock it down into a vise correct??

I've watched a few videos and read an install write up but they sometimes gloss over a few details as if we ALL understand...I spent allot of time cleaning my m16A2, but was only allowed to take it down so far...wish I could have ended up with the Armorers to learn something other than trigger pulling, rocket launching and tank I.D. -

[6bg6ga]

I have a jig that you put the upper in and then clamp it into a vice. It has another piece with a pin that aids in the gas tube alignment.

[6bg6ga]

Upon closer inspection the barrel nut doesn't seem to be 6061T6 in my rail kit.

[dkf]

The reason I questioned this is the info for my rail and barrel nut say do not exceed 30 ft lbs. Now, I don't question that the receiver will take the torque but I do question if my Monstrum barrel nut will.

What rail is it?

[6bg6ga]

Its a Monstrum rail.

[M-Tecs]

http://www.monstrumtactical.com/quad-rails/ar-15-keymod-handguards/ar-15-keymod-rail-handguard-12-inch.html

Please note that installation of a free float quad rail requires additional tooling and gunsmithing expertise. We recommend consultation with an experienced gunsmith. When installing the barrel nut, we recommend using 30-35 lbs of torque. The barrel nuts are made from 6061 grade aluminum which, although significantly lighter than steel barrel nuts, can be damaged under excessive force.

[dkf]

Looks like they cheaped out on the aluminum and anodizing to keep the price down. My ALG rails (Geissele uses it too) uses a 7075 aluminum barrel nut with a hard low friction anodize on the barrel nuts. The barrel nuts torque to standard specs. The ALG uses shims in conjunction with the included wrench and torque is precalculated based on rotation, target torque is around 50ft lbs if you follow the instructions. The ALG rails are very good rails for the money.