762×54R

7.62×54R, also written 7.62×54mmR, is a rimmed, bottleneck rifle cartridge developed by the Russian Empire and adopted in 1891 for the Mosin-Nagant service rifle. The R in its designation stands for rimmed, indicating its case design. It is a 7.62 mm cartridge used in rifles and light machine guns.

The cartridge has a 54 mm case length and is designed for a 7.62 mm projectile. Its rimmed case is compatible with the bolt-action and early gas-operated firearms that were standard in its era, contributing to reliable feeding and extraction in those platforms. The round remains the long-serving standard in several Russian and post-Soviet weapons.

Historically, 7.62×54R saw extensive use in World War I and World War II and continued as the standard Soviet cartridge into the late 20th century. Today it remains chambered in a number of weapons still in service or used by collectors and hobbyists, including the Mosin-Nagant family, the SVD sniper rifle, and machine guns such as the DP-28 and PKM.

Ammunition types include ball, tracer, armor-piercing, and incendiary rounds. Ball bullets typically weigh roughly 147–174 grains, with muzzle velocities commonly in the 800–860 meters per second range, depending on the exact load. Special-purpose rounds vary in weight and performance.

Production of 7.62×54R continues today from multiple manufacturers for military, law enforcement, and civilian markets. The cartridge is notable for its exceptionally long service life and persistence in a variety of rifles and machine guns across decades.