37mm M-1939

The 37mm M-1939 (61-K) is a Soviet-designed automatic anti-aircraft gun, widely used during and after World War II. It was effective against low-flying aircraft and light ground targets, serving with numerous countries globally.

Developed in the late 1930s by the Kalinin Artillery Plant under M. N. Loginov, the weapon was designed to fill a critical gap in the Red Army's low-altitude air defense and officially entered service in 1939. During World War II, it served as the backbone of Soviet divisional air defense, often mounted on trucks to create mobile self-propelled platforms, and was credited with destroying thousands of Axis aircraft. Following the war, the gun was extensively exported to Warsaw Pact and allied nations, seeing heavy combat in the Korean and Vietnam Wars. While obsolete by modern standards, it remains in active service or reserve with several militaries worldwide and laid the technological foundation for subsequent Soviet autocannon designs.