The 7.62×54r (7.62mm X 54mm r=rimmed) is a rimmed rifle cartridge developed by the Russian Empire and was introduced as a service cartridge in 1891. Originally designed for the bolt-action Mosin–Nagant rifle, it was used during the late Tsarist era and throughout the Soviet period to the present day. The cartridge remains one of the few standard-issue rimmed cartridges still in military use and has the longest service life of all military-issued cartridges in the world.
The American Winchester Model 1895 was also chambered for this cartridge per a contract with the Russian government. The 7.62×54mmR is still in use by the Russian military in the Dragunov and other sniper rifles, as well as some modern machine guns like the PKM. Originally, the round was designated as "Трехлинейный патрон образца 1891 года" – (Three-line cartridge model of 1891). It then became widely known under the designation "7,62мм винтовочный патрон" (7,62mm rifle cartridge). The round has erroneously come to be known as the "7.62mm Russian" (and is still often referred to as such colloquially), but, according to standards, the "R" in designation (7.62 × 54 R) stands for Rimmed, in line with standard C.I.P. designations. The name is sometimes confused with the "7.62 Soviet" round, which refers to the rimless 7.62×39mm cartridge used in the SKS and AK-based (AK-47) rifles.