Hey guys - I’ve had this one 7,62x39 in my collection for some years that has always looked kinda “off”. It’s kind of easy to tell why - the throat and its crimp looks very rough and irregular, and the rim and extractor groove is much thicker and longer than on regular 7,62x39.
From what I can tell this is very simply put a 7,62x45 that has been cut down and been through a 7,62x39 body size die.
See the pictures here…
Left-to-right bxn 7,62x39, the “mystery” round, bxn 7,62x45:
The headstamp of the round is “53 bxn I”.
The rim thickness and extractor groove length/angles is the same as on x45. As one can see the case is ever slightly so shorter than the factory x39.
Was this done in some sort of systematic effort, in Czechoslovakia or elsewhere, or is it possibly just some homemade reloading job/small-scale operation, to get use out of otherwise obsolete 7,62x45 ammo? I’d love to hear if there was any other known cases of this kind of case. Pun intended.