The Gustav submachine gun is a model of simplicity and effectiveness.
In 1969, Sgts. George Bacon and Newman Ruff used a sound-suppressed Karl Gustav submachine rifle to suppress North Vietnamese forces. Uncertain of the shooter’s whereabouts, the North Vietnamese withheld information, allowing the squad to flee. The small size and dependability of the Gustav made it popular with SOG and other US special operations groups. It fired with a straight blowback mechanism with a fixed firing pin.
Gunnar Johnsson, a weapons designer, produced the Karl Gustav m/45 for the state-run Karl Gustav rifle manufacture: It combined characteristics from numerous World War II-era submachine guns to equip the Swedish army with a reliable, simple-to-use automated infantry weapon. The Gustav’s straight two-row 36-round box magazine had a tapered feed that almost eliminated jams. By 1972, the gun had been phased out of US service; nevertheless, it was retained by Sweden’s Home Guard until the late 1980s.
Source: https://www.historynet.com/swedish-k-gun/
