Source of Metric Designations?

I posed this question on another thread but it may have become lost in the other discussions. So, I’ll ask it here:

Regarding the various metric designations for US cartridges, are there published official listings of them? The US designations can be found in the TMs that are available with a little on-line searching, but what about other countries? For example, where do I find a drawing of the 12.7 x 76mm (or 77mm) and it’s official designation? Is it officially referred to as the “BAT” cartridge? Etc. Etc.


The metric designations for U.S. cartridges in the form of caliber x length in m/m seems to represent two distinct schools. The earlier ones for such older American cartridges as the .22 Hi Power, .25-35, and the .30-06 were created in Germany before WW.2 under authority. Under whose authority I’m not sure, but either the German government or the equivalent of SAAMI. These were fixed in the same way that the 10.75 x 68 m/m Mauser was fixed.

In the post-WW.2 era metric caliber designations in the caliber x length format (once restricted largely to Germany and for centerfire rifles) have proliferated, but under what authority seems clouded to me. Certainly there are instances in which the namers of cartridges can’t decide what names to use (e.g. the Mannlicher 6.5 x 53 or 6.5 x 54 confusion). Jack


That’s kinda what I was thinking. They just “happened”. But I would have thought that the metric designation for a military cartridge, such as the Cal .50 M48, would have had something more official behind it.

Anyway, thanks for replying. I’d still like to hear from some of the guys overseas.


Ray I do not know why or how they came to the metric designations but the official German Bundeswehr designation of that round is 12.7x76 for example.

Ray, All ammunition used by NATO militaries has had National Stock Numbers since the mid-late 1960s. Each country has an activity to assign these NSNs along with the official name and description of the item. The one that does this for the US is the DOD Cataloging and Standardization Center in Battle Creek MI. My experience is with aircraft parts, but ammo also gets an NSN assigned and goes through the Cataloging and Standardization process which is the same or very close to the NSN assignment (and update) process for other DOD items and items from NATO nations.

I think there are some places you may want to look. The key words are ammunition interchangability and ammunition interoperability I suspect. The NATO Support Agency (NSPA) was formed recently and they probably have a play in this process.

I suspect the info is now all in a database now, but there may be some information on the internet.



Thanks Lew. Very informative documents, especially the first. I’ve saved them both to my files.