.50 BMG caliber (12.7x99, not Sov 12.7x108), allegedly AP, mfg'd in the Dominican Republic, berdan primed.
QC wasn't very good, AP core doesn't penetrate any armor plate, only about ball in core quality. Some rounds, you can hear the core rattling in the jacket if you shake the round. Some reports of extreme pressure. Prohibited from .50 cal competition, prohibited from use in Barrett .50 rifles.
Nice souvenir, but don't try to shoot it. Originally sold for 39 cents US in 10 round box quantities.