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.
AK-74 rounds for the same weight compared with the previous Soviet AK-47 and AKM and later 7.62×39mm chambered AK platform assault rifles. The AKS-74 ("S"—Russian: ; "Skladnoy", or "folding"), is a variant of the AK-74 equipped with a side-folding metal shoulder stock, designed primarily for use with air assault infantry and developed alongside the basic AK-74. Unlike the AKMS's somewhat fragile underfolding stock (modeled after the MP 40 submachine gun stock), the AKS-74 stock is fabricated from stamped sheet metal struts, machine pressed into a "U" shape and assembled by punch fit and welding. The stock has a triangular shape; it