The 61-K is the Soviet 37 mm automatic anti-aircraft gun developed from the late-1930s 49-K lineage and fielded as a mobile, clip-fed short-range air-defense weapon. It became one of the Red Army's standard light anti-aircraft guns, saw documented Soviet use around Moscow in 1941, was widely copied abroad, and remained visible in legacy arsenals such as Yemen's inherited air-defense inventory.
A Russian specialist restoration history of the AZP-39/61-K states that 37 mm 61-K guns were assigned to anti-tank regiments from July 1941 and that anti-aircraft guns used in direct fire played a major anti-tank-defense role during the Battle of Moscow.
Yemen's pre-2015 anti-aircraft artillery inventory included 37 mm 61-K guns alongside 57 mm S-60/AZP-57 pieces; reporting on Houthi-controlled air-defense forces describes small-caliber anti-aircraft guns being fired mainly against personnel and equipment, while still posing a short-range threat to aircraft and drones.
Role details61-K is the Soviet factory/index designation for the 37 mm automatic anti-aircraft gun accepted as the 1939 model; later rows distinguish the land gun from close copies, naval mounts, and self-propelled installations using the same gun lineage.
| Variant | Configuration | Designation notes |
|---|---|---|
| 37 mm automatic anti-aircraft gun M1939 (61-K) | Single-barrel towed land gun | Plant No. 8 developed the 37 mm weapon from the 49-K lineage in 1938, and it was adopted in 1939 as the 37 mm automatic anti-aircraft gun 61-K model 1939. |
| Type 55 | Chinese single-barrel copy | ODIN identifies the Type 55 as the Chinese version of the Russian M1939 (61-K) 37 mm towed anti-aircraft gun. Sources: Type 55 Chinese 37mm Towed Anti-Aircraft Gun - ODIN |
| 70-K | Navalized single 37 mm mount | NavWeaps describes the 70-K as a navalized 61-K accepted into Soviet Navy service in 1940 and produced through 1955. |
| ZSU-37 | Tracked self-propelled installation | The ZSU-37 mounted a single 37 mm 61-K gun in an open-roof turret on an SU-76M-derived tracked chassis. Sources: ZSU-37 - WeaponSystems.net |
The 61-K family is documented as firing 37x252SR shells, including the OR-167N projectile family identified by CAT-UXO.
| Ammunition | Ammunition type | Firing evidence |
|---|---|---|
 | 37x252mm HEI-T projectile | The 61-K source says the cannon fires 37x252SR shells, and CAT-UXO identifies the OR-167N as a 37x252 mmSR projectile in the M1939 family. Sources: 37 mm Automatic Air Defense Gun M1939 (61-K), 37mm or 167n m1939 projectile - CAT-UXO |
 | 37x252mm HEI-T projectile | The 61-K source says the cannon fires 37x252SR shells, and CAT-UXO identifies the OR-167 as a 37x252mm projectile in the M1939 family. Sources: 37 mm Automatic Air Defense Gun M1939 (61-K), 37mm or 167 m1939 projectile - CAT-UXO |
 | 37x252mm AP-T projectile | The 61-K ammunition table lists BR-167 alongside OR-167 and OR-167N, while CAT-UXO identifies BR-167 as a 37 mm M1939 projectile and JMU ordnance-guide material ties the UBR-167 cartridge to the M1939 gun. Sources: 37 mm Automatic Air Defense Gun M1939 (61-K), 37mm BR-167 (M1939) projectile - CAT-UXO, Projectile Identification Guide |
Soviet evaluation of Bofors 25 mm guns helped lead to the 49-K development path.
Sources: M1939 / Type 55 37mm Automatic Antiaircraft Gun, Russia / USSR 37 mm/67 (1.5") 70-K - NavWeaps
Factory No. 8 was ordered to develop a 37 mm weapon based on the 49-K design lineage.
Sources: M1939 / Type 55 37mm Automatic Antiaircraft Gun, Russia / USSR 37 mm/67 (1.5") 70-K - NavWeaps
Firing trials of the new 61-K were conducted.
Sources: M1939 / Type 55 37mm Automatic Antiaircraft Gun
The 61-K entered service and Soviet production began.
Sources: M1939 / Type 55 37mm Automatic Antiaircraft Gun, 37 mm Automatic Air Defense Gun M1939 (61-K)
The navalized 70-K version was accepted into Soviet Navy service, later becoming a major Soviet automatic naval anti-aircraft mount during World War II.
Sources: Russia / USSR 37 mm/67 (1.5") 70-K - NavWeaps
The SU-76M-based ZSU-37 carried a single 37 mm 61-K gun, but entered service after World War II combat use had effectively passed.
Sources: ZSU-37 - WeaponSystems.net
The 61-K designation anchors a wider 37 mm family: a towed Red Army gun, foreign copies, naval mounts, and a tracked self-propelled installation. The relationships below are lineage and installation context, not separate catalog links.
| Designation | Relationship | Service context |
|---|---|---|
| 61-K / M1939 | Baseline land gun | Developed from the 49-K path at Plant No. 8 and adopted in 1939 as the Red Army's 37 mm automatic anti-aircraft gun. |
| Type 55 | Chinese copy | ODIN identifies the Type 55 as the Chinese version of the Russian M1939/61-K towed 37 mm anti-aircraft gun. |
| 70-K | Navalized mount | NavWeaps describes the 70-K as a navalized 61-K accepted in 1940, with production continuing until 1955. |
| ZSU-37 | Self-propelled installation | The ZSU-37 used a single 61-K gun in an open-roof turret on an SU-76M-derived tracked chassis, giving the weapon family a late-war mobile anti-aircraft branch. |
