AK-74 be used by the majority of countries of the former Soviet Union. Additionally, licensed copies were produced in Bulgaria (AK-74, AKS-74 and AKS-74U), and the former East Germany (MPi-AK-74N, MPi-AKS-74N, MPi-AKS-74NK). Besides former Soviet republics and eastern European countries, Mongolia, North Korean Special Forces, and Vietnamese People's Naval infantry use AK-74s. The AK-74 was designed by А. D. Kryakushin's group under the design supervision of Mikhail Kalashnikov and is an adaptation of the 7.62×39mm AKM assault rifle and features several important design improvements. These improvements were primarily the result of converting the rifle to the intermediate-caliber high velocity 5.45×39mm cartridge.
AO-63 assault rifle is semi auto firing one barrel, the second in full auto firing both barrels with a 0.01 millisecond delay, the third is unique as at first it fires a two-round 6000rpm burst then one barrel in 850rpm full auto. The magazine is unusual as it has the main double column holding 30 rounds with a single column holding 15 rounds. AO-63 assault rifle The AO-63 () is a Soviet two-barrel AK derived assault rifle chambered for the 5.45x39mm round. It was designed by S. G. Simonov and P. A. Tkachev, and manufactured by TsNIITochMash. It uses a side by side