The Mkb 42(W), and the more successful Maschinenkarabiner 42(H) designed by Haenel, were predecessors of the Sturmgewehr 44 (StG 44) assault rifle.

[4] 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.

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.

[1] Submachine guns had existed since the First World War, but they used pistol caliber ammunition and lacked both the range and accuracy the German Army was looking for.

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.