The 122mm howitzer M1938 (M-30) was introduced into the Soviet Army shortly before World War II to replace the obsolescent World War I models. After the war the Ml938 became the standard divisional howitzer of the other Warsaw Pact armies. It also was sold to armies in other parts of the world. The M1938 is mounted on a box-section,so1it-trai1 carriage fitted with a shield. The recoil system consists of a hydraulic buffer above the tube, and a hydropneumatic recuperator below it. The breechblock is a hinged screw type. Care must be taken to distinguish the M1938 from the 152mm howitzer M1943 (D-1) which uses the same basic carriage.