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Pyzik
6 May 2014, 08:07
I have a BCM upper build from BCM. I installed the Samson rail this past weekend and needed to remove the barrel to install it due to my pinned FSB.

Got everything back together and was planning on heading out this weekend then it dawned on me, should I check the head space?
Same upper and same barrel re-mated.

Front sight (pinned) is straight and bolt seems to lock up fine.

Thanks!

GOST
6 May 2014, 08:54
No, the head space shouldn't change since the chamber extension is part of the barrel.

Pyzik
6 May 2014, 09:00
That's what I thought. I've been reading that it shouldn't.
Just never done it before and was a tad nervous for a second.

GOST
6 May 2014, 10:52
I know the feeling. Remember that you can buy Noveske barrels with head spaced bolts, installing the barrel doesn't change the head space.

UWone77
6 May 2014, 11:31
RA once told me that whenever they've used their go no-go gauge, they've never had one read no-go when using quality parts. Customers that have brought in their own homemade guns with parts unknown, well that's a different story.

Pyzik
6 May 2014, 11:37
I am confident then. Quality parts, BCM upper, BCM barrel and BCM BCG.
Barrel is tight, gas tube & sight are lined up.

gatordev
6 May 2014, 13:45
RA once told me that whenever they've used their go no-go gauge, they've never had one read no-go when using quality parts. Customers that have brought in their own homemade guns with parts unknown, well that's a different story.

On another forum (Calguns) a few months ago, Randal (AR15barrels.com) mentioned he was finding numerous builds sent to him with quality parts (post-panic manufactured) that weren't head-spacing correctly. He wouldn't name names, but he said it was the usual bunch that we all think are good to go. Personally, I didn't have a problem with my Centurion Arms bolt/barrel I just had put together, but since it's my only post-panic set of parts, I was a little nervous at first.

AR-10
6 May 2014, 23:55
Once the barrel and barrel extension have been torqued together and the gas port has been drilled, there is nothing that can be done to adjust headspace.

That doesn't mean it shouldn't be checked, but I don't mess around with "go" or "no go" gauges.

I use a Colt field gauge, you can order one from Brownells.

UWone77
7 May 2014, 11:01
On another forum (Calguns) a few months ago, Randal (AR15barrels.com) mentioned he was finding numerous builds sent to him with quality parts (post-panic manufactured) that weren't head-spacing correctly. He wouldn't name names, but he said it was the usual bunch that we all think are good to go. Personally, I didn't have a problem with my Centurion Arms bolt/barrel I just had put together, but since it's my only post-panic set of parts, I was a little nervous at first.

This doesn't surprise me. During the panic, I'm sure a lot of QC issues slipped by.

Iraqgunz
9 May 2014, 12:56
That's not entirely true. Headspace is measured from the front of the bolt face as well. Over time the headspace can change which is why the U.S military does an annual gaging, and why they use a Field Headspace gage. When we did the annual inspection, part of that was headspace, bore erosion, firing pin protrusion, firing pin hole gaging, etc...


Once the barrel and barrel extension have been torqued together and the gas port has been drilled, there is nothing that can be done to adjust headspace.

That doesn't mean it shouldn't be checked, but I don't mess around with "go" or "no go" gauges.

I use a Colt field gauge, you can order one from Brownells.