American work on a light high-speed rifle round in the 1950s produced the AR-15, later fielded as the M16 during fighting in Vietnam. Captured examples and ammunition reached Soviet testers through North Vietnamese channels in the 1960s.

After studying the 5.56 cartridge, Soviet planners issued a 1966 requirement for a similar 5.6 mm assault rifle. A design contest among several engineers ended with Mikhail Kalashnikov’s prototype selected after field trials from 1969 to 1973. The Soviet Army adopted the 5.45 mm AK-74 and related light machine gun in 1974.