Buying a new 5.56 barrel for an existing upper receiver I have. Previously when I've bought barrels for my projects I have been able to buy bolts from the manufacturers that were the correct headspace.(Kreiger and Compass Lake Eng.)

Not happening this time and I would like to know the correct way to check the headspace. I'm going to buy the headspace gauges but not sure of the best way to use them.

I know I have to strip the bolt of the extractor and ejector. Can I then check for the correct headspace with the barrel not assembled to the receiver or will I have to assemble the barrel to the receiver and check with the bolt in the bolt carrier?

Also looking for suggestions about who's headspace gauges to buy.

Any help and suggestions would be appreciated.

Thanks, Greg

I don't know how one would do it without it in the receiver as you need the bolt aligned properly with the barrel. But maybe.
In any case you have it right. Strip the bolt see what it closes on and go from there. I have a bunch of different ones and it doesn't seem to matter who made them. I have GI, Fostner, and Clymer don't think it matters. What does matter at some point is what dimensions are they made to and that is a very long discussion.

I bought this set from Brownell. Eliminates the need to strip the bolt.

Brownell

Can't help with checking w/o the barrel and receiver assembled.

You can do it w/o the receiver as your hjust seeing of the bolt will close on a go or no-go gage. Just put the barrel in a vise and then you will have both hands free for the bolt. Insert the go gage, then try and insert and turn the bolt to see if it closes(it should)

Then do it with the no-go gage, you should not be able to close it fully.

In the armory We never checked headspace as the barrel and barrel extension are set when they are assembled and are right or they wouldn’t go out to the fleet from that point.

When I was a unit armorer the small arms repair shop used these types of headspace gauges for arms room inspections. They could gauge everything they needed to without removing the ejector.

quote:

Originally posted by D_Steve:
I bought this set from Brownell. Eliminates the need to strip the bolt.

Brownell

Can't help with checking w/o the barrel and receiver assembled.

in my experience GI gauges don't have the issue of the ejector. Also its easy if you have a mill or a lathe to just lop off the interference part of the gauge. Or just get one without that issue. But also with care you can work around the issue.

Thanks to all for your input.

D Steve I ordered the set you linked. My plan now is to check the headspace before I install the barrel and again after its installed in the upper receiver.

I check all my AR builds with Forster headspace gauges. I use the go and no-go, not the "field".

Never had any barrel/bolt combo fail. It's good insurance but if you buy decent quality stuff you shouldn't have issues.

I thought the same, like why am I doing this after so many years of it not being an issue. Then I had a top-quality bolt (DD) and a top-quality barrel (Geissle) flunk. And that has convinced me to continue to do it. I suggest everyone does the same checking, but of course the failure rate you hear about is essentially nil.