bloop tube; bloop gun noun an M79 grenade launcher US,1971 Vietnam war usage. It is a single-shot, break-open, breechloading, shoulder-fired weapon.
— Peter Kokalis, SoliderofFortnue, p. 57, July 1992
[M]achine guns, automatic rifles, bloop guns, occasionally the mortar tubes, maybe the recoilles if there was one—would open fire into their sector of the wire and cleared approaches. — Cherokee Paul McDonald, IntotheGreen, p. 204, 2001