The Danuvia submachine gun, or the Király Géppisztoly, is a Hungarian submachine gun.
The design was conceived by Hungarian engineer Pál Király in the mid-to-late 1930s. In 1938 Király sent the blueprints to Birmingham Small Arms in Britain, who produced several prototypes. These prototypes were tested by the British Army but not adopted on account of their considerable technical complexity. By 1939, Király managed to get the weapon produced in his home country, and it was adopted by the Hungarian Army.
The Danuvia submachine gun was similar to a carbine, due to its size. While inspired by the Beretta Model 38, the Danuvia used a slightly more powerful round. Like the Beretta design, the magazine can be folded forward into a recess in the stock where it can be stowed away for easier storage.
The Danuvia uses lever-delayed blowback, using a patented two-part delayed blowback bolt. The fire selector is a circular cap on the rear of the receiver. The ejection port and the cocking handle are on the right of the receiver.
The Danuvia was originally designed as the 39.M; it was later modernized as the 43.M, with a distinctive curved magazine and a shortened barrel. The 39.M had a second variant which was the 39.M/A, featuring a folding wooden stock.
- Contrary to popular belief, the Danuvia 44.M was the basis of the Cristóbal carbine, and not the 43.M.