My opinion, and nothing more.
The headstamp is unknown to me. Unusual for it to be a “commercial” headstamp from Russia without a factory or makers’ mark in the headstamp.
The solid color primer seal is not typical for Russian cartridges.
The wear and chipping of the lacquer case finish, especially around the case mouth, tells me that it has been handled more than needed for the loading process. It could have been a regular cartridge that was disassembled to reuse the case, but I would think that common, military cases would be abundant, or even fresh empty ones.
If the cartridge was for underwater use and the primer is sealed, why not the case mouth too? Why is the steel projectile left bare and unfinished?
The projectile design does not seem like it would allow reliable feeding in a Kalashnikov type rifle, but maybe it was designed for a different system?
My first impression is that this is a “fake”, but in all fairness, how many authentic Soviet/Russian experimentals have any of us seen? Especially me!
Looking forward to learning more about this one!
Well, I have a cartridge with some similarities listed as a short track load. It’s a very long aluminium core, embedded in copper like material. You could say it’s saboted. It’s a 7,62x54 from Prvi Partizan made in 1995.
BOZ, the cartridges look similar but they are way different.