.50 BMG unknown

These .50 BMG dummies have shown up for years. Typical ball profile but black primer drilled off center and NO headstamp. Anyone know for sure about these ?

Brass or steel case? That blackened primer looks very Czech to me.

brass with M2 bullet. I have seen 4 over 50 years.

Guess that rules my Czech theory out then. Being brass cased and having an M2 bullet, and how long ago you have seen them. I would suggest items made up as movie props or something similar that ended up getting out into the collecting field, or action proving dummies made up at armoury level. But they must be factory as they have no hstp, and have never been dry fired as the primers anr unstruck, so must be “new” dummies.

I have had one for at least 30 years. Some say they are Remington display dummies but so far no proof. There are about 6+ known in collections- all the same.