762×39

7.62×39mm is an intermediate rifle cartridge developed by the Soviet Union in 1943 for use in the AK-47 and related firearms. It became the standard chambering for the AK family and many derivative rifles, achieving global proliferation and long service in numerous countries and conflicts.

Design and specifications: The round is rimless and bottlenecked. The case length is 38.7 mm and the overall cartridge measures about 57 mm. The standard bullet is 7.92 mm in diameter and typically weighs 122–125 grains (about 7.9 g). The most common military load is the 7.62×39 M43 full metal jacket, which exits a standard-length barrel at roughly 710–730 m/s, delivering about 1,550–1,700 joules of muzzle energy. The cartridge is designed for reliable operation in semi-automatic and fully automatic rifles with moderate recoil.

Variants and ammunition types: In addition to ball ammunition, 7.62×39 has been produced in armor-piercing, tracer, incendiary, and dummy variants. Armor-piercing rounds such as 7N23 and tracer variants have appeared in various arsenals, and different manufacturers have produced steel-core or specialty loads for particular roles.

Operational history and usage: Adopted by the Soviet Army in the 1940s for the AK-47 family, 7.62×39 has become one of the most widely used cartridge standards in the world. It remains in production and in service with many countries, particularly in platforms designed around the AK action. While some armies have transitioned to newer calibers, 7.62×39 continues to see extensive use in rifles, carbines, and light machine guns globally.