25 mm automatic air defense gun M1940 (72-K)

The 25 mm automatic anti-aircraft gun model 1940, plant code 72-K, was a Soviet autocannon that entered service with the Red Army in 1941. The weapon's mobility and rate of fire were unsatisfactory and production stopped at the end of the Second World War.

Source: Wikipedia — 25 mm automatic air defense gun M1940 (72-K) (CC BY-SA 4.0)