I know that this has probably been asked a thousand times.....but...what is the proper procedure for torquing the barrel nut on the upper receiver....and getting the gas tube to line up properly.
thanks in advance.

Forget the torque wrench - go to [url=http://www.ar15.com/forums/topic.html?b=3&f=4&t=173151]this thread[/url] for [b]The Famous Homo Erectus Barrel Mounting Method[/b].

Is that all there is....really...sounds to good to be true.

And what's that little saying about 'too good to be true' -- I forgot.

[;)]

Just did my first one the other night.

First and only rule is to get a receiver block and barrel wrench.  Got both of these through Midway for $62. to the door.  I also recommend a new gas tube "while your in there".

Made sure the receiver notch and barrel pin are snug, a small dab of grease on the receiver threads, put a three inch piece of gas tube in the bolt carrier nipple, slide carrier forward with gas tube through receiver, C clip and spring washer.  I tightened the barrel nut hand tight then set my torque wrench at 30 lbs and tightened.  The short piece of gas tube makes it easy to see when you're lined up.  I was half way between slots at 30 so I went to 35 without much change.  I just continued to go to the next slot which didn't take much effort and was well under the 80 lb max I have heard about elsewhere.  I had to back off a little and come at it again to insure that the tube was right in the middle of the nut slot.  All of five minutes.

Hoppy

and what's that saying about "work smarter, not harder?"

Hoppy, why get a new gas tube?

Just MHO:

1. This project was kind of a small "overhaul" of a rifle that had seen a lot of use and abuse before I acquired it so I bought all the parts I thought I would need before I started the job.
2. I had a little blow-by gas around the area where the tube enters the sight block.
3. Tweak listed this as one of the top three failure items.
4. I wasn't sure I wouldn't mung the old one up removing it.
5. I don't anticipate taking the barrel off again for quite a while.
6. I needed a short piece to use for aligning the nut.
7. And probably the most important...they're cheap!

If the truth be known, I probably could have gotten away with using the old one as I soaked the sight/tube junction with Hoppe's for a couple of hours before I removed it and it came out relatively easy.

Hoppy

Thanks!