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
Assault rifle and the 5.45×39mm cartridge. AK-74 production began in 1974, and it was unveiled in 1977, when it was carried by Soviet parachute troops during the annual Red Square parade. It would soon replace the AKM and become the standard Soviet infantry rifle. In 1979, the AK-74 saw combat for the first time in Afghanistan, where the lethality of the 5.45mm rounds led to the Mujahadeen dubbing them "poison bullets." The adoption of the 5.56mm NATO and the Russian 5.45×39mm cartridges cemented the worldwide trend toward small caliber, high velocity cartridges. In 1977, Austria introduced the 5.56×45mm Steyr AUG bullpup rifle,