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-12 fall 2013. However, on 23 September 2013, the "Izvestiya" tabloid wrote that, according to an anonymous source, the AK-12 will not be adopted or even undergo state tests due to shortcomings in preliminary tests. The AK-12 was to replace three previous of AK models and standardize assault rifles in the Russian military. The government's rejection of the AK-12 was because senior commanders said they had millions of stockpiled AK-74 models and did not need a new rifle. Though, trials will continue for law enforcement agencies. However, on 23 December 2014, the Russian Army announced that the AK-12, as well as