mystery ammo

[cruiser348]

A friend recently was given some ammunition that he isn't sure what it is and asked me for some help but so far I have been unable to identify it. My cartridge book is very limited on what it gives dimensions for and none of those listed seem to match what this cartridge is. The dimensions are as follows:
shell OD : .46
shell length: 2.102
slug OD : .309 @end of shell case
slug length: .855
overall length: 2.957
What I can make out of the headstamp is MMAPB (though what is listed as an A appears more as an upside down V because it doesn't have the cross). The datestamp is 1944.
From the pictures he sent me it appears to be either rimless or semi-rimmed. Any help that anyone can give me in this situation is very much appreciated.

[Xracer]

Closest thing I can see is 7.62 Nagent:

Shell OD (Shoulder Diameter): .453
Shell Length (Case Length): 2.11
Slug OD (Bullet Diameter): .310
Overall Length: 3.02

If you have an interest in IDing cartridges, I'd suggest you pick up a copy of "Cartridges Of The World".....it makes fascinating reading.

Amazon.com has a special on it for $19.57: http://www.amazon.com/exec/obidos/search-handle-form/102-2894980-0080948

[cruiser348]

I actually already have a copy of cartridges of the world. The only issue being that the only section in my version atleast that has the case dimensions listed is that for current American rifle cartridges, so all I was able to do through this reference was to eliminate the possibility that it is what they consider current. Perhaps newer versions go farther into detail on case dimensions for other categories of cartridges.
I have however already eliminated the 7.62X54 which is the closest in terms of dimensions I have found because this case is not a rimmed case like the 7.62 is. Was just hoping perhaps these dimensions seemed familiar to someone from something they had worked with in the past.

[280freak]

Cruiser -

Have you tried asking about this over at Flhunter's Curio and Relics Forum? Lots of pretty knowledgeable folks over there.

[cruiser348]

Thanks for the advice, could you post a link to that page I'd like to go check it out? The ammo has finally been identified though it is Argentine Mauser, but am always looking for new sources of information on here.