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
Assault rifle type weapon with a bi-pod, a stronger receiver, and a longer, heavier barrel that would eventually replace the RPD light machine gun. The AK-47 was widely supplied or sold to nations allied with the USSR, and the blueprints were shared with several friendly nations (the People's Republic of China standing out among these with the Type 56). As a result, more AK-type weapons have been produced than all other assault rifles combined. As of 2004, "of the estimated 500 million firearms worldwide, approximately 100 million belong to the Kalashnikov family, three-quarters of which are AK-47s." The U.S. Army was influenced