I have two old military headspace gauges that I can't find any info on.

Both are Squires Gage Company

ORD. DEPT etc, etc CAL. 30

One is stamped C-7719 A

1940 22

2.185 oal

The other is C-7719 G

1946 18

2.191 oal

I believe one is a field and the other a no-go.

I can't get an accurate measurement to determine what they are.

Anybody out there know what these are from the stampings?

Both 06 gages are WWII and every one I have seen has the dimension rolled into it. During WWII and postwar there was a gage for each one thousandth starting from 1.940 to 1.950. The most common ones encountered today are 1.940 Min, 1.946 No Go, and 1.950 Field Rejection, that is because these three were issued to company level armorers. The others were used at depots for precise measuring of headspace, thus fewer were made. I have run into a few gages that are obvious WWII production but totally unmarked. Those were production errors that got passed the inspectors.No those are not years of the contracts, they are the dimensions. If you look carefully there should be a period after the first digits.

Thanks SmokinJ.

Of all the stuff on the net I found it hard to believe I couldn't find a thing on the gages.

I sent an email to the CMP but have yet to hear back. I figured if anyone would know, it'd be them.

I'll have to get the magnifying glass out to look for the decimal point.

The dimensions as in 1.940” and 1.950” would be the distance from the bolt face to the shoulder (case body/shoulder juncture for a short chamber), the dimension 2.185” and 2.191” would indicate the arsenals and SAAMI had not agree on a standard, the military had their standards and SAAMI had theirs.

SAAMI says: when using the .375 datum for measuring the length of the chamber the reading should be 2.048 to 2.058, the 2.048 would be go-gage length. The 2.185” and 2.191 would indicate the military used a different datum that was smaller in diameter than the SAAMI .375” and the difference between 2.191” and 2.185 is .006”. meaning the longer gage would not allow the bolt to close on a (shorter than) no go-gage length chamber.

What can be done with the gages you have, I would measure the length of the gages from the datum of .375” to the head of the case, then I would write down the measurement and compare with ‘what SAAMI says.

It is possible to make a tool that measures from the datum, I have not been able to convince reloaders it can be done.

The dimensions as in 1.940” and 1.950”, when measuring case length the case body/shoulder juncture is 1.948 in the perfect world for a minimum length/full length sized case/store bought/factor made.


F. Guffey