Buy Red Army Elite Range Pack 7.62x39mm 180RD 123gr FMJ – Ammo Online. 7.62x39mm is an intermediate rifle cartridge developed for the Red Army towards the end of World War II. It was later adopted for use in the SKS and AK rifle systems. Since the end of the 1940s, global use of this cartridge has made it one of the most well known and widely distributed rifle cartridges in history. The 7.62x39mm round is often touted as being superior to the Western 5.56x45mm round.