Soviet 5.45x39mm

The 5.45x39mm cartridge is a rimless bottlenecked rifle cartridge. It was introduced into service in 1974 by the Soviet Union for use with the new AK-74 assault rifle. It gradually supplemented then largely replaced the 7.62x39mm round in service.

History
The 5.45x39mm cartridge was developed in the early 1970s by a group of Soviet designers and engineers under the direction of M. Sabelnikova. Further group members were: L.I. Bulavsky, B.B. Semin, M.E. Fedorov, P.F. Sazonov, V. Volkov, V.A. Nikolev, E.E. Zimin and P.S. Korolev.

The 5.45x39mm is an example of an international tendency towards relatively small sized, light weight, high velocity military service cartridges. Cartridges like the 5.45x39mm, 5.56x45mm, and Chinese 5.8x42mm allow a soldier to carry more ammunition for the same weight compared to their larger and heavier predecessor cartridges and produce relatively low bolt thrust and free recoil impulse, favoring light weight arms design and automatic fire accuracy.