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 The selector and safety were combined into a single control-lever/dust-cover on the right side of the rifle. And, the bolt-handle was simply attached to the bolt-carrier. This simplified the design and production of the rifle. The first army trial series began in early 1948. The new rifle proved to be reliable under a wide range of conditions with convenient handling characteristics. In 1949, it was adopted by the Soviet Army as "7.62 mm Kalashnikov assault rifle (AK)". There were many difficulties during the initial phase of production. The first production models had stamped sheet metal receivers with a milled trunnion