An assault rifle is a rifle that uses an intermediate cartridge, a detachable magazine, and can switch between semi-automatic/fully automatic fire. … It must have an intermediate-power cartridge: more power than a pistol but less than a standard rifle or battle rifle. Currently the most used assault rifle in the world along with its variant, the AKM, the AK-47 was first adopted in 1949 by the Soviet Army. It fires the 7.62×39mm M43 round. The M16 was first introduced into service in 1964 with the United States Armed Forces.