Tips for first barrel install

Gear Head

Gear Head

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Just received the last piece needed to finish my upper. When installing the barrel nut I've read about seasoning threads by going through a tightening/loosening sequence before final torquing. Also is there a preferred type of anti-seize to use on the barrel nut/barrel extension? Also, my barrel has one dimple for the gas block and my gas block has two set screws. Do I just use the one or go ahead and tighten both?

Sorry for the noob questions. This will be my first barrel installation.
 
For grease be a little careful ... DO NOT USE ANY CONTAINING GRAPHITE! Graphite and aluminum can interact which can lead to corrosion. While many will say it’s not the only thing out there but I’ve always used AeroShell and never had a problem.
 
A dab of anti-seize or quality moly grease on the threads and barrel nut thrust surface against the barrel will do.
The advantage of snugging, backing off, snugging the barrel nut just helps smooth out the load bearing surfaces. It probably does more to make us feel better than just tightening to 40 ft/lb and calling it a day.
 
Yes: clean, loctite, and tighten both gas block screws. Preferably to the correct specified torque.
I also completely cover barrel around gas port and under gas block with loctite.
 
Torque specs for the barrel nut from what I've found is 40-80 ft/lbs. That seems like a large window. Is there any advantage to being on a specific end of that range? I don't have to time anything so I can torque to whatever.
 
Gear Head said:
Torque specs for the barrel nut from what I've found is 40-80 ft/lbs. That seems like a large window. Is there any advantage to being on a specific end of that range? I don't have to time anything so I can torque to whatever.
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Not really the wide range helps get it to where the barrel nut lines up for the gas tube


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Gear Head said:
Gotcha. Didn't know if blue would just melt out after the first heat cycle.

Red is permanent. I think there's a hi temp that's green?
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Unsure on the green but I've always used blue unless I don't want it to come back off.......ever. Lol
 
I use blue as well. You'd think it all burns off, and it does to some degree, but maintains a tighter seal.

Anything in the gas port get blown out first shot. I used to not do this, but a local top 3gun guy suggested I do this and it has worked great.
 
There is a reason for using proper grease and a reason for for the tighten/loosen, tighten/loosen method. It’s called proper torque spec. The tighten/loosen process mates the actual shape of the adjoining threads so that proper torque can be obtained. Proper grease that is called for in the manual for assembling uppers also assured that proper torque will be met. It will not be true-to-spec otherwise, I don’t give a damn what your torque wrench reads.

I can’t believe that anyone would spend the money on quality parts, buy the tools, and then spend the time needed to assemble an AR and not spend the extra 2 minutes to follow the proper torque methods and get the proper grease.

But they’ll be damn sure to have some whiz-bang crap-nugget part somewhere on their rifle because “accuracy”.

Sorry, I sound like an grumpy old man today. This topic just gets under my skin though. And it comes up on every gun forum at least twice a year.
 
Isn't that kind of the point of this thread? Anybody can screw a barrel nut on. The point of me asking was for clarification on specific points and to arrive at the proper way to do it.
 
Gear Head said:
Isn't that kind of the point of this thread? Anybody can screw a barrel nut on. The point of me asking was for clarification on specific points and to arrive at the proper way to do it.
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Yes it is the point and my reply wasn’t intended at you. There are always replies to these threads with “slap some grease on it and torque ‘er down” and it’s not the correct way to do it.

I was snarky in my reply and for that I apologize. I need a snickers. Lol
 
Gear Head said:
Torque specs for the barrel nut from what I've found is 40-80 ft/lbs. That seems like a large window. Is there any advantage to being on a specific end of that range? I don't have to time anything so I can torque to whatever.
Click to expand...


I meant to answer this in my reply as well.

As close to 40lbs is what you want. If you do the tighten/loosen several times method, then you’ll good to go at the lower end of the torque range.
 
This thread has been helpful to me. So far, I've only ever bought assembled uppers, and hadn't branched out into building my own. Now that I'm confident with lowers, I'd like to try building my own upper, exactly like I want it.
 
I have some moly grease in the garage but I went ahead and ordered some aeroshell off Amazon. $12 for 1.4 oz. Should get quite a few rifles built and it will be here tomorrow.
 
Good choice. I’ve used several types of grease over the years, including Lucas Red & Tacky (which is surprising well-spec’d for upper assembly).
 
Everyone has their own ways ... to me torquing the barrel nut is not always an exact science but the tighten backoff retighten is my choice and makes it easier to time it for alignment of the gas tube. Depending on the type barrel nut used and correct timing I’ve had some come in on the light side to some pushing the manufacturer’s upper spec. Best suggestion is after you’ve run it a little go back and make sure all your components haven’t shifted ... barrel nut, gas block and muzzle device especially on the upper. Double check your BCG for gas key and gas rings along with the castle nut on your buffer tube ... just to make sure.
 
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40ft/lbs doesn't feel like much.. I've torqued and loosened 3 times. Torque to 40 again and let her ride?
 
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Gear Head said:
40ft/lbs doesn't feel like much.. I've torqued and loosened 3 times. Torque to 40 again and let her ride?
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The AeroShell will make it seem easy and another question is how is the timing of the barrel nut for the gas tube? I’ve seen people go as high as 75-80 ft-lbs to time it correctly ... I am usually 50-60 ft-lbs.
 
NCFubar said:
The AeroShell will make it seem easy and another question is how is the timing of the barrel nut for the gas tube? I’ve seen people go as high as 75-80 ft-lbs to time it correctly ... I am usually 50-60 ft-lbs.
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I don't have to time it.

The problem I'm having now is the damn roll pin for the gas block. I dropped it earlier and it took 20 min to find it. I have collapsed one end just a hair and I still can't get it started
 
Gear Head said:
I don't have to time it.

The problem I'm having now is the damn roll pin for the gas block. I dropped it earlier and it took 20 min to find it. I have collapsed one end just a hair and I still can't get it started
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Get a bigger hammer lol


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I got it, kinda. The roll pin made it through one side of the gas block, the gas tube, and bottomed out on the other side of the gas block. I don't have anything small enough to stick through the roll pin to try and straighten it.

Doesn't really matter because the seekins low pro gas block contacts the SLR rail. I guess I'm going to have to order the SLR gas block and use the seekins on a 300 blackout pistol I'm planning.
 
It’s nice not having to time the barrel nut with gas tube. Sounds like you about have it worked out except the gas block. Last pic looks good.
 
I had a hard time getting the gas block back off. As mentioned above I slathered the barrel in blue loctite and I guess it had enough time to start to set. I was able to get it on by hand. Hammer and a block of wood wouldn't budge it. Ended up putting a crescent wrench behind it and hammer the wrench.
 
Gear Head said:
I had a hard time getting the gas block back off. As mentioned above I slathered the barrel in blue loctite and I guess it had enough time to start to set. I was able to get it on by hand. Hammer and a block of wood wouldn't budge it. Ended up putting a crescent wrench behind it and hammer the wrench.
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Next time hit it with some heat and it will slide off easier.

Gun looks sweet!
 
NKD said:
Next time hit it with some heat and it will slide off easier.

Gun looks sweet!
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This was after hitting it with a map torch lol. Fellow didn't want to come off. And I was afraid of messing something up either with the wrench or heat..
 
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Could’ve done a mag dump with the rail off.

ETA: On second thought, probably not a good idea with a brand new barrel. Haha
 
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Gear Head said:
This was after hitting it with a map torch lol. Fellow didn't want to come off. And I was afraid of messing something up either with the wrench or heat..
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Invest in a good heat gun. I have a Milwaukee 2 temp (500° & 1000° F) heat gun I use for even red Loctite. No flame and since it is air flow heat I can actually control how hot a part gets ... even sink wrap. For small stuff like screws with Loctite I just take a soldering iron (most are about 750°F) and hold it directy on the head of the head of the screw until the metal in the screw conducts enough heat down to raise the temp high enough break down the Loctite.
 
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We also use the Milwaukee Dual heat gun here in Astan. We use Red Loctite on the set screws. Suggest that you don't lather down the barrel under the gas block with Loctite just the screw. 40-80 lbs is given for a standard USGI barrel nut which has to be timed to align the notches for the gas tube. Not need usually for a free floated tube, I usually do 50 lbs for a DD RIS II rail here.

CD
 
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