Got a field gauge, now what?

[Doc McCoy]

I bought a field gauge from Bushmaster. To check the headspace correctly,
is it nescessary to remove the extractor and ejector ( according to the
slightly limited instructions), put the firing pin back in, and try to close the
bolt/carrier on the gauge? By "closing" do they mean when you get that
audible click when inserting the bolt and pushing it in so that the rifle will
close.

Please pardon my ignorance on this matter. If anyone can describe the
procedure it would be greatly appreciated.

[308]

Doc McCoy-

Just follow the instructions on the Bushmaster headspace gauge sheet.

Your field guage is used to determine excessive headspace only...you really should not have a problem with headspace on a new AR barrel since headspace is determined at the factory. Nothing wrong with checking though...I use a Go and No-Go.

But to answer the question, you should remove the extractor and ejector so that they do not interfere with the bolt face pressing on the field guage. These parts are easily removed by pushing the retainer pins out with a small starret punch and light hammer.

The field gauge will measure excessive headspace and should not allow the bolt to turn and lock under any circumstances...this should answer your "closing" and "audible click" question.

308

[Doc McCoy]

Thanks for your reply 308. I bought a used Colt upper that I would like to
check ouy before using. I was advised that I could remove just the extractor
and simply "feel" when pushing on the bolt/carrier, the ejector being pushed
in. I tried this and I could feel it push in a little after contact, but no way
would it close on the gauge. I compared this with the same procedure on my
brand new Bushy upper and got identical results.

For some reason, I was a little hesitant to try and remove the ejector after
having a slight problem removing the pin with a punch, it was very tight.
I'm in no hurry and want learn to do it correctly. I will try again to remove
the ejector.

Any thoughts on the method used thusfar? Also, does a military field gauge
work without removing them? If so, who sells them?

[XHairs]

Check with the guy selling some here:
http://www.assaultweb.net/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=12;t=216132