7.62x39mm steel core

The 7.62×39mm (aka 7.62 Soviet or formerly .30 Russian Short) round is a rimless bottlenecked intermediate cartridge of Soviet origin that was designed during World War II. The cartridge is used by both militaries and civilians alike, due to the worldwide proliferation of the Soviet SKS and AK-47 pattern rifles, as well as RPD and RPK light machine guns.
Shortly after World War II, the AK-47 was designed, later becoming the world's most widespread military-pattern rifle. The cartridge remained the Soviet standard until the 1970s. It was largely replaced in Soviet service by the 5.45×39mm cartridge, which was introduced with the new AK-74 rifle, and continues in service with the modernized current-issue Russian Armed Forces AK-74M service rifle, as well as the AK-12 rifle. In the 21st century the 7.62×39mm remains a common service rifle chambering, including for newly developed rifles like the AK-15.

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