[Bebe]

Until I came here, I had never considered the interface between barrel and reciever to be anything but "true & square".
Well sir, I've ordered a tool to square my reciever.

QUESTION:
Am I looking to remove just enough material to give the barrel a square seat? i.e. different widths?
Or am I looking for a consistent width face all the way around the reciever?

Is it ok to chuck the tool up in my variable speed drill?
High speed?
Slow speed?
No pressure?
Little pressure?
A lot of pressure?

Will the tool need to be occasionally trued/squared?

 

[Bebe]

I've built several AR's, never even considered that the barrel extension and barrel mounting ring might not be "quite" square....but it makes sense!
I watched several on YouTube.
Most preferred a relatively even ring. A couple guys weren't concerned with even, just a smooth, clean edge all the way around.

Tanlover442
Very correct, you can always take a little more off. Putting it back can be a real bear! LOL!

 

[Bebe]

Picked up a "squaring tool".
Now I have 4 AR's to debarrel and square up. 😀

Thanks folks!

 

[Bebe]

Got the tool, disassembled my 6.8 and squared the (Anderson) reciever. Sadly, I have been unable to test it to see if it made any major difference. So stinking hot, it's probably going to be this fall, or at least cooler temps before I venture forth! LOL!
I learned a LOT from the first few AR I assembled.
ALWAYS scrub (and I mean SCRUB!) the chamber before assembly.
Lube the threads (very little) before installing the barrel nut.
True up receiver before installing barrel.
Torque barrel nut to 35 ft/lbs.
Wait 5 minutes.
Back off barrel nut and torque to 35 ft/lbs again.
Wait 5 minutes.
Back off barrel nut and torque to 45 ft/lbs and align notches for gas tube.
Does the torque, release, torque, release, torque make a big difference?
I dunno...but it sure soothes my OCD thinking I've stressed and relieved the nut and threads a couple of times.

 

[Bebe]

Constructor got it. Torque to desired ft/lbs, then tighten to the next hole.

I'm not under any mistaken idea that there is any "perfect" barrel assembly method. I just do what I do that works

Were I building some target rifle that I had to guarantee met some accuracy standard, I'd probably do things differently.
I haven't built (assembled?) hundreds of AR's. Each of them (probably 15, give or take) has been a learning experience that I enjoyed immensely.....and hope to "assemble" many more! LOL!