762×39mm

7.62×39mm, often written 7.62×39 or 7.62x39, is a rimless, bottleneck rifle cartridge developed by the Soviet Union during World War II for selective-issue infantry rifles and automatic weapons. It was adopted in 1943 as the M43 cartridge for the SKS and the emerging AK-47 family and soon became the standard Soviet intermediate cartridge.

The cartridge uses a 7.62 mm bullet with a diameter around 0.311–0.312 inches (about 7.92 mm). The case length is 39 mm, and the overall length is roughly 57 mm. Standard loadings use projectiles typically around 122–125 grains (about 7.9 g) with a full-metal jacket. Muzzle velocity for common loads is approximately 715–735 m/s, delivering roughly 1,900–2,000 joules of muzzle energy. The design prioritizes reliability, heat tolerance, and ease of manufacture for mass production.

In service, 7.62×39mm became the standard cartridge for a wide range of Soviet and allied weapons, including the AK-47, AKM, SKS, and light machine guns such as the RPD. It was widely exported and copied, leading to extensive use across the Soviet bloc and various conflicts worldwide. Variants and ammunition types have included armor-piercing, tracer, and subsonic loads; some specialized rounds exist but the conventional ball round remains the most common.

Global usage persists in many older and some current military forces, and the cartridge continues to be produced and employed in civilian markets, surplus arms, and regional firearms production. It remains closely associated with the AK-47 family and comparable 7.62×39 chambered designs.