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-74 5.45×39mm Russian ammunition). Very little is known about this model. The AK-74M was also the basis for the new Russian AK-100 family of Kalashnikov firearms: the AK-101 assault rifle and AK-102 carbine (both chambered for the NATO-standard 5.56×45mm NATO cartridge), AK-103 assault rifle and AK-104 carbine (both chambered for the 7.62×39mm round) and the 5.45×39mm AK-105 carbine. The AK-101, AK-102, AK-103 and AK-104 are destined primarily for export, while the AK-105 is slated to replace the AKS-74U with the Russian Armed Forces. Additionally, the 5.45×39mm AK-107 and 5.56×45mm NATO AK-108 rifles have a balanced recoil system to reduce felt recoil