The Kalinin plant started work on a 25mm-caliber automatic anti-aircraft gun in 1939 meant for regiment-level use. The gun would borrow many of its components from the 61-K 37mm anti-air gun, which was already a finished design. The new design received the designation ZIK-25, and later, 72-K. The 72-K underwent factory tests on October 11, 1939, and later field tests from April 15 to May 25, 1940. Pronounced gun vibration and tracer cups detaching from shells were found during field tests, which prompted the development of new shells without such defects. These shortcomings did not interfere with the adoption of the gun, however, as it was accepted into service as the 25 mm automatic anti-aircraft gun model 1940 in the same year. Its chief designer, Loginov, did not live to see the gun enter mass production, as he died of tuberculosis on October 28, 1940. His post was taken by his deputy, Loktev, who also contributed greatly to the creation of the 72-K.
