T. R. Fehrenbach shares an anecdote (in This Kind of War) that I heard first heard about Russians on the eastern front:
Mount saw that some attacking Chinese had no rifles; as they advanced, they waited until a companion was hit, then took his weapon.
Four ranks in line attacking simultaneously. First rank throwing grenades. Second rank firing “burp” guns. Third rank with rifles. Fourth rank picking up the weapons of those that had fallen.
Probably a commissar in the rear with pistol shooting any shirkers or malingerers.
The heck is a “burp” gun?
Heck, Joe Haldeman was issued a useless M-16 in Vietnam, don’t know what else he could do but grab a good one from someone who was down.
A “burp” gun is a submachine gun.
Specifically, the “burp gun” was what the average GI called the PPSh-41 in colloquial terms. The Soviets called it the “Papasha”, or “daddy”.
In WWII, the term would typically refer to the German submachineguns, whose higher rate of fire than American ones got them the “burp gun” nickname. Korean war, it was the PPSh-41. Which had a really, really high rate of fire–You’d empty a stick magazine with a trigger pull, and the 71-round drum was only good for a few bursts.
Typically, of course, the majority of the rounds would go anywhere but where the gunner was wanting them to.