Does anyone have a recommendation as to where I can pic up a "true" military Go, No-Go and field guages for checking headspace? All I can find are civi versions.  Maybe someone has a PN from somewhere? Brownells etc. all seen to be the SAAMI gauges and they're out anyway...Thanks...

K_SNIPER

headspace

M16 Max. Headspace Gage   4933-00-070-7814          7799734              $30.00           Disassembly of bolt not needed, gage is cut for extractor and ejector clearance

(edit: why go all the way to the bottom :-))

Thanks......!

Quoted: http://www.billricca.com/prod06.htm M16 Max. Headspace Gage   4933-00-070-7814          7799734              $30.00           Disassembly of bolt not needed, gage is cut for extractor and ejector clearance

How does one use that gauge?  I assume insert it into the chamber and then close the bolt/bolt carrier----right?  With a field gauge, the bolt should NOT close on the gauge------right(?)----for if it does close on it, that would be an indication of excessive headspace---right?

I have a field reject,  if the bolt closes it is time to rebarrel or swap around bolt lookinf for one that allows that allows the bolt to stay unlocked.

For me I think it would be cheaper to just replace the bolt.

Now I just have to find the field reject guage, I think it is out in the shop somewhere.

You just drop it in....Lightly push BCG forward. TM spec old version says maximum of 8.5lbs force...so..as they put it...finger pressure althought the updated TM says to hold the upper vertical, with the field guage installed and the BCG group resting on it and then add a 8.5lbd set of discs to the top of the BCG group. Bolt SHOULD NOT ROTATE TO LOCKED POSITION. A little ridiculous even for my anal self. The carrier should protrude from out the back of the upper. If the bolt closes. It's time for a new bolt or barrel swap. I also use a SAMMI spec "FIELD" which is very very very close to a NATO / Milspec NO-GO on fresh builds. I use the Sinclair tool to disassemble the bolt first since the ejector has to come out. I prefer that a new build bolt and barrel NOT pass a NATO No-Go. I use the NATO Field/Reject every 6 mos. as a check as I fire off a lot of ammo.

K_SNIPER

Thanks for the insights and instruction, guys!  Appreciate it!  CBR

I got my Field gauge from someone on the EE. $25 for a NIW military field. I have Clymer G/NG gauges, but I need a bolt tool to take out the extractor.

Oh yeah, make sure your chamber and bolt face are spotless.