The NS-23 was a 23 mm (0.91 in) 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. The NS-23 round was derived from the 14.5×114mm anti-tank round by necking it out to 23 mm. A synchronized version, designated NS-23S (for synchronized), was used for fixed installations firing through the propeller arc. The NS-23 was replaced in service by the Nudelman-Rikhter NR-23 around 1949.