Perhaps the most common military rifle in the world, the AK-47 is an assault rifle designed by the Soviet, Mikhail Timofeevich Kalashnikov. In its most common form, introduced in 1949, the AK-47 fires a 7.62mm caliber bullet, specifically from the intermediate-power 7.62x39 cartridge (e.g., more energetic than the pistol cartridges fired from submachine guns), from a distinctive curved 30-round magazine.
Introduced in 1974, the similar-appearing AK-74 fires a smaller 5.45mm bullet. Following a world trend in using smaller caliber bullet, the AK-74 is to the AK-47 as the U.S. M-16 is to the 7.62mm M-14. The AK-74M fires the same ammunition, but is made of lighter and more rugged materials and features a side-folding stock.
Kalashnikov-designed rifles have an excellent reputation for reliability and needing minimum maintenance; the U.S. M-16, especially in its earliest versions in the Vietnam War, was more prone to jam unless carefully maintained. The original M-16 also had a smaller 20-round magazine.
Due to the rifle being relatively cheap, it became a favourite of terrorist groups such as the Provisional IRA.