question on barrel nut torque

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Ernest II

New member
Finally got my computer to play you tube videos. So I was seeing how to change the barrel on my RRA. One read said to torque it to 30 lb then increase in increments of 10 up to 80 lb while ligning the gas tube holes up when getting to the 80 lb mark. OK then Larry Potterfield shows how to install a free float tube and he says to torque the barrel nut to 30 lb(period) He never mentions going up to 80 by 10,s. SO how much do you torque the barrel nut and not hurt accuracy. If I understand correctly the amount of torque will really affect accuracy. Im uneasy about letting a shop do this for me. The shop where I bought the gun says they do this type of work but most of those guys are pretty young and I just feel uneasy about having my great shooting AR screwed up or scratched up by clumbsy smith work.
Thanks for any help.
Daryl Pelfrey
 
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Most manufactures give you a range. The couple I've seen have been 30-50 and 40-80 iirc.

The problem that I've had on the one that I installed is that the gas tube doesn't line up in that range.... I'm gonna have to file two of the holes into one longer oval hole....
 
Torque to 30 pounds and then tighten to next hole in barrel nut to line up tube.

That will give you approximately 50 pounds.

Don't over think it.
 
Thanks Hail Caesar thats what I will do. Thanks blopez50.AT least if I have the shop do the work I can act like I know something about whats going on. I would still rather do this myself.Accuracy is really the main thing. Oh and no big ugly scratches on my toy.LOL How far are you from indpls Hail Caesar?
Thanks Daryl P.
 
What I have always read is to torque it to 30, back it off, torque it to 30, back it off, then torque it to whatever it takes to get the notch to align for the gas tube as long as your final torque is between 30 and 80.
 
Originally Posted By: Hail CaesarTorque to 30 pounds and then tighten to next hole in barrel nut to line up tube.

That will give you approximately 50 pounds.

Don't over think it.


i would like to see you get it to the next alignment point if 30lbs is barely past one notch.
30lbs is the minimum torque you should have on it to align the nut so gas tube slides freely through, to as much as 80lbs. i had one that was too loose at one gas tube alignment point and to tight to get it to the next gas tube alignment point. i filed that upper reciever face a couple strokes at a time until i could get the barrel set back enough to get to the next hole.
i have no idea why they don't just say minumum 30lbs no more than 80lbs.
 
Thanks Guys, I am sure getting interested in theses AR,s. I was always a bolt gun fan and still like my bolt guns but this is a new adventure. I may eventually build my own.
Daryl P.
 
kyle,

Minimum is 30 and 80 is the rated maximum.

Did you use grease and mated the threads before you tightened the nut? Every once and a while 30 barely clears a notch and the next notch is a bear to get to...but you can do it.

And why file on the face of the receiver? Just (if you really have to) Dremel out the one barrel nut tab.

Al
 
If you're this deep I don't think there's any "may eventually" in it! If you have the $, buy the couple tools now and put this one on for yourself... It's only a matter of time!

The AR is a blast and it's great for someone like me who has ZERO skill but can still build one.
 
Originally Posted By: Ernest IIThanks Guys, I am sure getting interested in theses AR,s. I was always a bolt gun fan and still like my bolt guns but this is a new adventure. I may eventually build my own.
Daryl P.

I say jump right in. It isn't rocket science at all.

I had a 11 year old build one a couple of weeks ago. All I gave him was a few pointers when he got stuck.

Al
 
Keep in mind that installing a barrel is not a simple case of torquing the bbl nut to a given spec or proper index. It's a PROCESS of mating the threads of your upper receiver to the bbl nut. You need to tighten to at least 30# torque and then back the nut loose and retorque. This process continues until the gas tube hole in your bbl nut is properly aligned. You MAY be able to achieve this with multiple attempts at 30# of torque. I usually torque and loosen 4-5 times at 30# before bumping the torque and then do so in 10# increments, making 3-4 attempts at each torque before increasing (never exceeding 80#). The male threads on the receiver are fairly malleable, take your time and it's a simple process. Rush things and try to get it in one shot....you'll shear the indexing pin on your bbl extension or worse. ALWAYS use grease on your threads!
 
I agree with stormking. 30 is where they seem to shoot the best. Bu the next notch is not a bad thing if it wont line up at 30 after a few attempts. You can get a upper reviever vice block from brownells for around 40$ and a dpms wrench for around 20-30.
 
Originally Posted By: dwayWhat I have always read is to torque it to 30, back it off, torque it to 30, back it off, then torque it to whatever it takes to get the notch to align for the gas tube as long as your final torque is between 30 and 80.

Most directions that I have read are 30-50 foot lbs range. Also they generally tell you to torque and remove at least 3 times to insure correct fit.
 
Originally Posted By: KlrDrvrAnyone here go to the extreme of squaring/facing the upper receiver before mounting the barrel?

I did a couple without any problems.....until my last assembly. I put a good quality barrel (BHW) on a mil spec upper and had nothing but problems. 2 1/2"-4" groups at 100 yds. Every group had a crazy flier. Crown looked good and BHW had good reputation. Barrel was torqued to 40 in lbs. Gas block was was not over torqued and had Troy FF tube. Out of frustration I pulled it apart and and trued the receiver face. I never indicated it (used lapping tool, not lathe), but upper was way off. I trued the face of the upper, re assembled it, and headed to the range. At 100 yds, gun now shot 22" to left. Once dialed in, problem solved.

After settling on load (60 gr Nosler BT, 25.1gr TAC, Win NT brass, CCI primers) the last group I fired at range was 3 shot, 0.465", 200 yds. Not all groups were this good, but 3 shot groups at 100 yds were routinely under 0.750", down to the 0.3s".

I've got a 16" Lothar Walther 223 wylde barrel sitting on top of the safe now and a 18" Lothar Walther barrel in 6x45 ordered, and when I scrape up the money to assemble, I assure you I will check the face of the receiver for true. I plan on making a fixture for the lathe, but have read that uppers can vary from 0.997"-1.00", so I won't turn anything until I buy the upper.

Sorry for being so long winded..
 
Originally Posted By: Ernest IIThanks Hail Caesar thats what I will do. Thanks blopez50.AT least if I have the shop do the work I can act like I know something about whats going on. I would still rather do this myself.Accuracy is really the main thing. Oh and no big ugly scratches on my toy.LOL How far are you from indpls Hail Caesar?
Thanks Daryl P.

I think it is about 4 hours. Come on down and I will do any work you want.
 
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Originally Posted By: RabonI haven't used a torque wrench in years, it not rocket surgery don't over think it.
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Good point. 80ft/# is a boatload of force. If you use the snug, loosen, approach to correct index, you'll never approach anywhere near that max torque.
 
I haven't put together many ARs but it is very easy so do some reading and buy the tools, it will be money well spent because you will build another one (or 4). I've always read/heard most ARs will get the best accuracy with the minimum torque needed on the barrel nut. Like anything, it's not a given but seems to be the big trend in them. Best way to get the minimum needed is like stated above, torque and loosen, then torque again at least 3 times, more if you're close to getting it lined up. You may have to step up the torque to get it to the next hole even with multiple tightenings. The best way, instead of increasing torque above 50lbs is to lap the front of the upper so it will align. All that said, it is very simple but it's kind of like reloading, it is simple but once you start doing it you make it complicated to make the best product as you can. Is it necessary to lap receivers? In most cases, not at all. Is it necessary to turn case mouths? For 99% of people, definately no. Do both give you benefits? You bet. Start easy, and you'll be fine. My first AR shoots .75 MOA with factory loads and I didn't know most of this lapping etc business.
 


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