 The Germans cancelled production in 1942 in lieu of its smaller brother, the 17 cm Kanone 18 in Mörserlafette, which could fire almost twice as far, but resumed production in 1943.Beginning in 1942, the 21 cm M 18 was one of a pair of weapons to have been mounted on production Geschützwagen Tiger self-propelled guns.A prototype was under test at the end of the war and was captured by American forces.