Firearm & Gun Forum - FireArmsTalk.com

Firearm & Gun Forum - FireArmsTalk.com (http://www.firearmstalk.com/forums/)
-   AR-15 Discussion (http://www.firearmstalk.com/forums/f20/)
-   -   barrel nut question (http://www.firearmstalk.com/forums/f20/barrel-nut-question-103764/)

string1946 02-07-2014 08:28 PM

barrel nut question
 
As I have mentioned several times, I am in the process of building a rifle and this is my first upper build. I have everything but the barrel which should be here within the month I hope. The way I understood the correct way to install the barrel was to use anti-seize compound on the threads and to tighten the barrel nut to 30 ft/lbs and then loosen it up and retighten it and repeat that 3 times to allow the barrel to seat correctly. Then to tighten to 35 ft/lbs before going just a little bit farther to align the gas tube holes. The forearm I have is a YHM customable 12" and the instructions say to just tighten the barrel nut hand tight and them enough farther to align the gas tube holes. They don't mention any anti-seize compound or anything else and skip the tighten/loosen thing. I read on another forum that someone questioned them on that and they said it wasn't necessary unless your using a steel barrel nut and their's is aluminum. This is going to be a target rifle so I'm not planning on taking it into battle so the aluminum doesn't bother me. I plan to do it the way I planned to begin with but was just wondering. Is the anti-seize compound not necessary because the barrel nut and receiver are both aluminum and not dissimilar metals? Is the tighten/loosen thing still a good idea?

JonM 02-07-2014 10:15 PM

Tightening and loosening is only needed once. Its not really needed at all but it does help seat the barrel.

Proper torque is between 30-60ft lbs. Set the wrench to 30 tighten it. Then set it to 60 and align a hole. Proper alignment may not be achievable in such cases its ok to take a dremel and remove a tooth from the nut.

I use anti sieze on all barrel installs regardless of metals. A small tube is like a couple bucks. I take a qtip get some compound and wipe in a line across the threads of the nut. If you over do it, it makes a godsawful mess.

When you are instlling a barrel do not use a upper reciever vice block use a barrel vice block made from hard wood. Upper reciever blocks will damage the upper when your torquing in foot pounds.

SSGN_Doc 02-07-2014 10:16 PM

I have that same handguard on one of my rifles. I stil used the anti-seize greese, and still torqued it and released, and retorqued, three times before seating. I think my final torque ended up being about 45 Ft/lbs to get the holes to line up. Haven't had any problems, and been shooting the rifle for over five years now with that handguard.

string1946 02-08-2014 12:17 AM

Thanks for the advice. I have anti seize at my bench and planned to use anyway and the tighten/loosen thing couldn't hurt so why not. I will have to check on the wooden barrel vice block. I have a upper receiver block but not one of those. I would guess it would have match the contour of the barrel.

Sent from my SCH-I925 using Firearms Talk mobile app

SSGN_Doc 02-08-2014 12:24 AM

Quote:

Originally Posted by string1946 (Post 1500990)
Thanks for the advice. I have anti seize at my bench and planned to use anyway and the tighten/loosen thing couldn't hurt so why not. I will have to check on the wooden barrel vice block. I have a upper receiver block but not one of those. I would guess it would have match the contour of the barrel.

Sent from my SCH-I925 using Firearms Talk mobile app

It doesn't have to match contour exactly. I have an aluminum barrel vice block. I use a couple thicknesses of bicycle innertube that have been glued together on either side and lay them in the barrel channels before tightening the vice.

string1946 02-08-2014 12:56 AM

Quote:

Originally Posted by SSGN_Doc (Post 1500996)
It doesn't have to match contour exactly. I have an aluminum barrel vice block. I use a couple thicknesses of bicycle innertube that have been glued together on either side and lay them in the barrel channels before tightening the vice.

I have been reading a little about them and how make one. Pretty much two hardwood blocks drilled either 1/16 to 1/32 less than barrel OD. My drill press should make that pretty easy. Also some use friction tape and some rosin to help with the grip. Guess I need to find a video of one being used.

Sent from my SCH-I925 using Firearms Talk mobile app

JonM 02-08-2014 01:34 AM

Quote:

Originally Posted by string1946 (Post 1501022)
I have been reading a little about them and how make one. Pretty much two hardwood blocks drilled either 1/16 to 1/32 less than barrel OD. My drill press should make that pretty easy. Also some use friction tape and some rosin to help with the grip. Guess I need to find a video of one being used.

Sent from my SCH-I925 using Firearms Talk mobile app

i would go half the diameter of the barrel. rosin really helps. i degrease the section to be clamped.

string1946 02-08-2014 02:14 AM

Quote:

Originally Posted by JonM (Post 1501045)
i would go half the diameter of the barrel. rosin really helps. i degrease the section to be clamped.

Makes sense to me. The barrel is .936 at the gas block. Sounds like 1/2" would be about right. Also what I read said to squeeze the crap out of it. You won't hurt the barrel as the wood gives way before you hurt the barrel. Just squeeze till you hear wood cracking. Sounds a little excessive to me.

Sent from my SCH-I925 using Firearms Talk mobile app

JonM 02-08-2014 04:48 AM

That's correct. You can't hurt it with wood blocks. They will come apart long before anything happens to the barrel.

When I was getting the wife's savage apart the first time I had it cranked with enough force to withstand 150+ftlbs of torque. Savage waaaaaaaay over tightened that nut. When I got the gun torqued correctly it went from 5moa to .25moa. I eventually had to cut the nut off.

Oak is a great wood for blocks. If the barrel is inline with the grain its probably going to split the wood.

Ibmikey 02-08-2014 01:51 PM

Jon, You have me a bit perplexed, block the barrel and torque the nut against an unsupported upper receiver? It would seem to me the steel nut upon contacting the aluminum receiver would transfer the torque and the index pin would be the only thing to keep the receiver from turning. I hope I am not confusing everyone, using a clam shell vise supports the receiver, the barrel does not need support, torque is then applied to a solid point. I have installed/removed 100 + barrels with a receiver vise without incident but never contemplated leaving the receiver just hanging. Get my brain back on track expanding your method as I am always looking for "a better mousetrap".


All times are GMT. The time now is 11:53 AM.

Copyright ©2000 - 2015, Jelsoft Enterprises Ltd.