The AK-47 is a selective-fire, gas-operated 7.62x39mm assault rifle, first developed in the Soviet Union by Mikhail Kalashnikov. The designation AK-47 stands for Kalashnikov Automatic Rifle, 1947 Model (Russian: Автомат Калашникова 47, Avtomat Kalashnikova 47). It is officially known as Avtomat Kalashnikova (or simply 'AK'). It is also known as a Kalashnikov or Russian jargon Kalash.
Design work on the AK began in the last year of World War II (1945). After the war in 1946, the AK-46 was presented for official military trials; and, in 1947, the fixed-stock version was introduced into service with select units of the Soviet Army. An early development of the design was the AKS-47 (S—Skladnoy or "folding"), which was equipped with an underfolding metal shoulder stock. In 1949, the AK-47 was officially accepted by the Soviet Armed Forces and used by the majority of the member states of the Warsaw Pact.
Firing the 7.62x39mm cartridge, the AK-47 produces significant wounding (including hydrostatic shock) when the projectile tumbles and fragments in tissue; but it produces relatively minor wounds when the projectile exits the body before beginning to yaw.
The original AK-47 was one of the first true assault rifles. Even after six decades—because of its durability, low production cost, and ease of use—the model and its variants remain the most widely used and popular assault rifles in the world. It has been manufactured in many countries and has seen service with regular armed forces as well as irregular, revolutionary and terrorist organizations, worldwide. The AK-47 was the basis for developing many other types of individual and crew-served firearms. More AK-type rifles have been produced than all other assault rifles combined.