The M-42 was a 45-mm Soviet light semi-automatic anti-tank gun. Its full official name is 45-mm anti-tank gun model 1942 (M-42) (Russian: 45-мм противотанковая пушка образца 1942 года (М-42)). These guns were used from 1942 until the end of World War II. Old stockpiles were returned to service in January 2025 in the Russo-Ukrainian War.

The M-42 was developed by the No. 172 Plant in Motovilikha as an upgrade of the 45 mm anti-tank gun M1937 (53-K). The gun received a longer barrel (20 calibers more than the previous one, so it was a 45 mm/L66), 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 crews to kneel while serving the weapon. Some minor changes were also introduced in order to speed up production.

These guns were used from 1942 until the end of World War II. In 1943, due to its insufficient anti-armor capabilities against new German tanks such as the Tiger, Panther and Panzer IV Ausf H, the M-42 was partially replaced in mass production by the 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 the Panther and Panzer IV Ausf H. Fragmentation shells and canister shot gave the gun some anti-personnel capability.

Mass production of the M-42 ceased in mid-1945. The total number of guns produced is 10,843.

On the 24th of January 2025 a video appeared of an M-42 gun being destroyed by a Ukrainian drone operator in the occupied Russian territory in the province of Kursk. This indicates that some of these guns have reentered service with the Russian armed forces.

• Ammunition types:
  • Armor-piercing
  • Fragmentation
  • Canister
  • Smoke
• Projectile weight:
  • AP: 1.43 kg (3.15 lbs)
  • APCR: 0.85 kg (1.87 lbs)
  • Fragmentation: 2.14 kg (4.71 lbs)

Penetration
Type	100 m (110 yd)	500 m (550 yd)	1,000 m (1,100 yd)	1,500 m (1,600 yd)	2,000 m (2,200 yd)
APBC-HE	71 mm (2.8 in)	54 mm (2.1 in)	40 mm (1.6 in)	32 mm (1.3 in)	28 mm (1.1 in)
APCR	108 mm (4.3 in)	74 mm (2.9 in)	46 mm (1.8 in)	-	-

• Shunkov V. N. - The Weapons of the Red Army, Mn. Harvest, 1999 (Шунков В. Н. - Оружие Красной Армии. — Мн.: Харвест, 1999.) ISBN 985-433-469-4
• Koll, Christian (2009). Soviet Cannon - A Comprehensive Study of Soviet Arms and Ammunition in Calibres 12.7mm to 57mm. Austria: Koll. p. 423. ISBN 978-3-200-01445-9.

Media related to M-42 45 mm anti-tank gun at Wikimedia Commons

• 45 mm anti-tank gun model 1942 ar rustrana.ru (in Russian)