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+--- Thread: Build update (/showthread.php?tid=10036)
Build update - Bill257 - 10-23-2015
Received my barrel (18in BHW by PF), it cleanly machined, finished, and overall looks great. Test fit to the Aero upper on deck for this rifle. Cleaned the upper and the barrel - not the supper tight fit I had hoped for... Not loose, but able to line it up and slide the barrel home with minimal effort. I considered shopping for another upper in hopes of getting a tighter barrel / upper fit. But, after some consideration decided to go with the Areo I have on hand.
Planned to bed the barrel to the upper all along. Previously builds it seemed little of the locktite could have remained in place, on this one some will likely remain in place to do the job it is intended to do.
On the up side, feed ramps lined up well and there is a smooth transition.
Waiting on the gas block, so I have plenty of time to go through the parts I have prep everything for assembly.
Build update - LRRPF52 - 10-23-2015
Square the face, bed it, and use a lot of torque when installing the barrel nut, at least 65ft-lbs. Read up on Robert Whitely's accurizing techniques for the AR15.
Build update - Steamburn - 10-23-2015
Don't forget to lap the front of the upper before installing the barrel:
Brownells Lapping Tool:
http://www.brownells.com/gunsmith-to...000182_d_11376
Build update - LRRPF52 - 10-23-2015
That's what squaring the face means, you lap it if it needs it. A lot of the uppers I've been seeing lately haven't needed it, but the tool is great for checking squareness.
It's also one of the tips mentioned in Robert Whitley's AR15 accurizing techniques.
Build update - Bill257 - 10-24-2015
The receiver has been squared... the process just confirmed it was square to start with. Glad I did it anyway as it won't be something to think a later had that step been skipped. Will report on torque values after instillation.
I did read Robert Whitley's article, excellent. Luckily I came across the article before discovering the gas block didn't get ordered. So, I was able to get a clamp on style rather than a set screw style block that I used in the past. Although, never expected two small screws would be able to distort the bore- I'd have expected a set screw to strip out long before doing anything that could degrade accuracy.
Build update - jim_bob - 10-24-2015
+1 for Aero uppers. Good luck with your build!
Build update - Bill257 - 10-24-2015
New record for torquing a barrel - almost 100 foot pounds to get perfect alignment. It was close in the low 90s and went up in small increments to get zero interference. I was on my last try before pulling it apart and lapping the upper again to make a bit more room. Glad I did not have to do that.
Build update - 37L1 - 10-24-2015
Bill257 Wrote:New record for torquing a barrel - almost 100 foot pounds to get perfect alignment. It was close in the low 90s and went up in small increments to get zero interference. I was on my last try before pulling it apart and lapping the upper again to make a bit more room. Glad I did not have to do that.That's pretty tight. Ever try barrel shims?
Build update - Bill257 - 10-25-2015
Yep it is tight - maybe tighter than I should have gone. Given that, all seems well and don't anticipate any problems.
Never used shims. Nothing against shims. But, like I said I'd run the lapping tool again. Betting a minute with that would have allowed the previous opening to line up at a torque range I was happy with. If that didn't work out it would be shim shopping time.