Gryazev-Shipunov GSh-23
The Gryazev-Shipunov GSh-23 (Russian: Грязев и Шипунов ГШ-23) is a twin-barreled 23 mm autocannon developed in the Soviet Union, primarily for military aircraft use. It entered service in 1965, replacing the earlier Nudelman-Rikhter NR-23 and Rikhter R-23.