Nudelman-Suranov NS-23
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The NS-23 was a 23 mm aircraft cannon designed by A. E. Nudelman, A. Suranov, G. Zhirnykh, V. Nemenov, S. Lunin, and M. Bundin during World War II as a replacement for the Volkov-Yartsev VYa-23 cannon. It entered service in 1944. Wikipedia
Muzzle velocity: 690 metres per second (2,300 ft/s)
Rate of fire: 550 rpm
Shell: 23×115mm