The K-61 cannon was a Soviet 37 mm towed anti-aircraft gun from the interwar period and World War II. Its first prototypes were created in the late 1930s, and serial production continued in 1939-1945, ending with the production of about 20,000 copies of this weapon in the USSR. The initial velocity of the missile oscillated around 870-880 m / s, and the rate of fire reached 180 rounds per minute, with a maximum vertical range of 6,700 meters.
The first work on the K-61 cannon began in 1935, with the 25mm Bofors gun, acquired in large quantities. Initially, efforts were made to recalibrate it to 45 mm, but finally in 1938 it was decided to focus efforts on the 37 mm caliber cannon. After successful test shootings in the same year (1938), the gun was adopted by the Red Army. It was an automatic cannon with a wedge lock, powered by cartridges with 5 rounds of ammunition each. It was characterized by a good rate of fire, good range of the shot, and above all: low failure rate, good mobility in difficult terrain and a short transition time from the marching position to the combat position, which oscillated around 25-30 seconds! It is estimated that during World War II, this type of cannons damaged or destroyed approximately 14,500 enemy aircraft. After the end of World War II, it was licensed in the PRC, Poland and North Korea. It was also used in many countries, including Angola, Bulgaria, Bolivia, Egypt, Finland, Iraq, Israel, Malaysia and Vietnam.