Firearm a battle rifle such as the Karabiner 98k, but the chief differences defining an assault rifle are select-fire capability and the use of a rifle round of lesser power, known as an intermediate cartridge. Soviet engineer Mikhail Kalashnikov quickly adapted the German concept, using a less-powerful 7.62×39mm cartridge derived from the standard 7.62×54mmR Russian battle rifle round, to produce the AK-47, which has become the world's most widely used assault rifle. Soon after World War II, the Automatic Kalashnikov AK-47 assault rifle began to be fielded by the Soviet Union and its allies in the Eastern Bloc, as well as
AK-47 a Simonov design. In 1946, a new design competition was initiated to develop a new assault rifle. Kalashnikov submitted an entry. It was gas-operated rifle with a short-stroke gas piston above the barrel, a breech-block mechanism similar to his 1944 carbine, and a curved 30-round magazine. Kalashnikov's rifles AK-1 (with a milled receiver) and AK-2 (with a stamped receiver) proved to be reliable weapons and were accepted to a second round of competition along with other designs. These prototypes (also known as the AK-46) had a rotary bolt, a two-part receiver with separate trigger unit housing, dual controls (separate safety