25 mm automatic air defense gun M1940 (72-K) (Russian: 25-мм автоматическая зенитная пушка образца 1940 года (72-К)) was a Soviet 25 mm caliber anti-aircraft gun used during the Great Patriotic War. The gun was developed from the end of 1939 to the beginning of 1940 at 8th Kalinin Artillery Plant under the guidance of its Chief Designer Mikhail Loginov, supervised by Lev Loktev. The cannon was given the factory code 72-K before being accepted into service by the Red Army as the 25 mm automatic air defense gun M1940.