762×39

Developed during and after World War II, the 7.62x39mm cartridge was first chambered in the RPD light machine gun. 7.62x39mm ammo is primarily used in SKS and AK rifles and delivers good medium-range performance. Although no longer used by the Russian military for front-line service, it is extremely common anywhere AK-pattern rifles are used. This cartridge has a tapered steel case that aids in its feeding and extraction; this taper gives AK magazines their “banana” shape.

7.62 x39 better than 308

The 308 Winchester has almost 40% more case capacity compared to the Russian 7.62×39 (56 gr vs 35.6 gr). This makes a lot of sense as the 308 Winchester cartridge case is a good half-inch longer than its Russian counterpart – a longer cartridge will mean more case capacity.