Head Space

[JaxCatm]

At work if we have an M16 or M4 that won't head space we have a list of items to check. I.E. we change bolts and try again. If that does not work we try a new barrel with the original bolt and so on until we get everything right. My question is what the hell can you do if you only have one barrel and one bolt and the head space is off?

[LukeMacGillie]

What headspace gauge(s) are you using?

[JaxCatm]

We are using standard GO/NO-GO gauges. I couldn't really tell you who makes them because I don't run the PMEL program for our shop.

[LukeMacGillie]

The first thing to do is make sure the gagues are military style that you dont have to remove the ejector to get a good reading.

Check your throat erosion,

Im off to the range so will check back this evening.

Luke

[Quib]

My question is what the hell can you do if you only have one barrel and one bolt and the head space is off?


From my personal experience, nothing really.

You've pretty much covered all the bases. Your options are, as you stated:
-old barrel with new bolt
-old bolt with new barrel
-new barrel and new bolt, which more than likely will head space, but there are those ocassions where even new parts will not HS.

[JaxCatm]

Thanks for the advice guys. I was just double checking to make sure we were not missing anything on the list.

[LukeMacGillie]

Alrighty, not to talk down to you, just dealing with the strange set of circumstances with doing a diagnosis over the net.

You said you have the GO/NO GO gauge, not gauges, so I cant tell if you have 1, 2, or 3. (A set is usually a GO, NO-GO and Field gauge)

I find the best one to use is just the NO-GO gauge. Put it in the chamber, then attempt to close the bolt. If the HS is good, the bolt will not close.

Im currently TDY so dont have my manuals, perhaps someone could post the NSN's or PN's for the various gauges?

Luke

[JaxCatm]

The chamber is just cut really long. I have no idea what the hell they were thinking when the thing was at the manufacture. Anyway it wasn't us the gauge or the bolt just a bad barrel. And Luke don't think your talking down to me. I had the T.O.'s and manuals right in front of me and I was scratching my head. And to clear things up it was the NO-GO gauge I seldom use anything else. I was working with a new barrel so the throat erosion was out of the loop.