Is that what was known as a ‘burp gun’?
I believe the “burp gun“ was actually the Soviet PPSH 41; it had a very high cyclic rate. We encountered Chinese communist troops armed with those in Korea.
The MP38/MP40 SMGs had a slower rate of fire.
I could be wrong though… I know the G.I.’s referred to it as the Schmeiser….
Now that I think of it, in the movie, Von Ryan’s express, he hands, Trevor Howard, and MP 40 and says “here take the Schmeiser”…