The M-42 was developed by the Plant 172 in Motovilikha as an upgrade of the 45mm M1937. The gun received a longer barrel, shells with more powerful cartridges, and a thicker shield (7 mm instead of 4.5 mm), but of hinged construction as a need for reduced profile, requiring the weapon to be serviced by crews while kneeling. Some minor changes were also introduced in order to speed up production.
These guns were used from 1942 until the end of the war. In 1943, due to its insufficient anti-armor capabilities against new Nazi tanks such as the Panzer IV Ausf H, Panzer V Panther and Panzer VI Tiger, the M-42 was partially replaced in mass production by more powerful 57 mm ZiS-2 anti-tank gun. The M-42 remained in production, however as it was quite effective against lighter vehicles and could pierce the side armour of Panther and Panzer IV Ausf H. Fragmentation shell and canister shot gave the gun some anti-personnel capability.
Mass production of M-42 ceased in mid-1945. The total number of guns produced is 10,843.
Weight – Combat: 625 kg (1,378 lbs), Travel: 1,250 kg (2,756 lbs)
Shell – 45 x 386 mm. SR
Calibre – 45 mm/ 68 (1.77 in)
Carriage – Split Trail
Elevation – 8 to 25 degrees
Traverse – 60 degrees
Rate of Fire – 15-20 rounds per minute
Muzzle Velocity – 870 m/s (2,854 ft/s)
Maximum Range – 4.55 km (2.84 ,mi)