The Russian Model 1891 Mosin-Nagant bolt-action rifle was among the earliest military firearms designed to use smokeless powder cartridges. Both rifles and carbines using the design by Imperial Russian Army Colonel Serge Mosin and Belgian arms maker Emile Nagant have been manufactured in China, Finland, France, North Korea, Russia, Switzerland, and the United States, and remained in military service at various places around the world for more than 60 years. Early models featured octagonal shaped receivers, while later models had round receivers.
Mosin-Nagant rifles are characterized by their massive, almost ungainly action which includes an integral five-round, single column fixed magazine. Simplicity of design and operation helped make these some of the most “soldier-proof” bolt action military rifle ever made. A cartridge interrupter in the magazine design helped make the Mosin-Nagant the most positive-feeding of any design which uses rimmed ammunition. Because the Mosin-Nagant design was used so widely and for so long, there are many different sub-models with various barrel lengths and features, but the action is essentially the same on all.
Ammunition for the Mosin-Nagant rifles is designated 7.62x54R. The 7.62 indicates the bore diameter in millimeters (.30-caliber). The 54 indicates the length of the cartridge in millimeters, and the “R” indicates it is a trimmed case.