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
Comparison of the AK-47 and M16 use, low production costs, and reliability were perfectly suited for the Soviet Army's new mobile warfare doctrines. More AK-type weapons have been produced than all other assault rifles combined. In 1974, the Soviets began replacing their AK-47 and AKM rifles with a newer design, the AK-74, which uses 5.45×39mm ammunition. The M16 entered U.S. service in the mid-1960s. Despite its early failures, the M16 proved to be a revolutionary design and stands as the longest continuously serving rifle in American military history. It is a benchmark against which other assault rifles are judged. The U.S. Military has largely replaced the