The Maschinenkarabiner 42(H) or MKb 42(H) (machine carbine Model 1942 (Haenel)) was an early German assault rifle firing an intermediate round of World War II.

[3] However, a combination of military orthodoxy, limited funds and the arms development restrictions of the Versailles Treaty led Germany to adopt the Mauser Karabiner 98K on 21 June 1935 to replace the Gewehr 98.

Since most combat took place at ranges less than 400 m (440 yd) a less powerful round could be used, which would mean a soldier could carry more ammunition, the weapon could be shorter, lighter and—with less recoil—the gun could be an automatic.

The specification called for a new weapon which was larger than a submachine gun, more accurate, longer ranged and more maneuverable than a full sized rifle.

[5] The receiver and trigger housing with pistol grip were made from steel stampings, which were attached to the barrel assembly on a hinge, allowing the weapon to be folded open for quick disassembly and cleaning.

Another set of modifications added a hinged cover over the ejection port to keep it clean in combat, and rails to mount a telescopic sight.

By one account, the gun saw action as early as April 1942 when 35 of the only 50 prototypes then in existence were parachuted into the Kholm Pocket near Leningrad as part of a resupply of the defenders.