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
Automatic rifle well as an entire line of weapons built on the same system, one of the most famous being the MP5 SMG. The first confrontations between the AK-47 and the M14 (assault rifle vs battle rifle) came in the early part of the Vietnam War. Battlefield reports indicated that the M14 was uncontrollable in automatic mode and that soldiers could not carry enough ammo to maintain fire superiority over the AK-47. A replacement was needed: A medium between the traditional preference for high-powered rifles such as the M14, and the lightweight firepower of the M2 Carbine. As a result, the Army