The most used firearm in history, along with its successor, the AKM, is the AK-47. It was first adopted in 1949 by the Soviet Army, and uses the 7.62×39mm M43 round.

The M16 was first introduced into service in 1964 with the United States Armed Forces. It uses the 5.56×45mm NATO cartridge.

An assault rifle is a rifle that has a removable magazine, automatic-fire and semi-automatic modes, and uses intermediate cartridges. These cartridges do not have as much power as other rifles, like hunting rifles or battle rifles, but have more power and penetration than pistol cartridges fired by sub-machine guns.

Two rifles made in Italy and Russia before World War I are sometimes called assault rifles. The Germans were the first to use assault rifles in large numbers.