Recently acquired this and of course am curious about its intended use. Was told it was a variation on the 7.62 x 38.5Rmm Russian Nagant (which it’s dimensions are identical to), but was informed it was for some sort of experimental Russian submachine gun possibly from the 1930’s. Headstamp is: “T П З 32” or “T П З 52” - the top of the year is cut off. Bullet is a flat nosed GMCS with 2 pin stabs.
Any thoughts, pictures?