The Mosin–Nagant is a five-shot, bolt-action, internal magazine–fed military rifle. Known officially as the 3-line rifle M1891 and informally in Russia and the former Soviet Union as Mosin's rifle, it is primarily found chambered for its original 7.62×54mmR cartridge.

Bolt-action is a type of manual firearm action that is operated by directly manipulating the bolt via a bolt handle, most commonly placed on the right-hand side of the firearm. The majority of bolt-action firearms are rifles, but there are also some variants of shotguns and handguns that are bolt-action. A firearm using bolt-action mechanism is colloquially referred to as a bolt gun.