The MP40, short for Maschinenpistole 40, was a German submachine gun introduced in 1940 and widely used by Wehrmacht forces during World War II. Its folding stock and fully automatic fire made it iconic in films, documentaries and games like Call of Duty and Battlefield. Recordings of its firing have circulated as stock effects for decades, becoming a go-to choice when creators need period-accurate automatic gunfire rather than a generic pew pew sound effect.