Bulgarian 1954 production but what does the 10 stand for? Sportsman Guide referred to it as quote: With "10" stamp that proves the "Commie" authenticity. Nice clean stuff 600 rnds for $100.64 Smelled like history when I opened the tin.
I think that is the factory number. Try rooting thru 7.62x54.net. They have a batch of scoop on the MNs.
I had some of that some years back - half of it had deep recessed primers - I had to turn my firing pin out a bit more to insure proper function. Otherwise, it shot fine. It was highly corrosive though! Clean well after shooting it.