The Mosin–Nagant is a bolt-action

Bolt-action

Bolt action is a type of firearm action in which the weapon's bolt is operated manually by the opening and closing of the breech with a small handle, most commonly placed on the right-hand side of the weapon...

, internal magazine-fed, military rifle

Rifle

A rifle is a firearm designed to be fired from the shoulder, with a barrel that has a helical groove or pattern of grooves cut into the barrel walls. The raised areas of the rifling are called "lands," which make contact with the projectile , imparting spin around an axis corresponding to the...

 invented under the government commission by Russian and Belgian inventors, and used by the armed forces of the Russian Empire

Russian Empire

The Russian Empire was a state that existed from 1721 until the Russian Revolution of 1917. It was the successor to the Tsardom of Russia and the predecessor of the Soviet Union...

, the Soviet Union

Soviet Union

The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....

 and various other nations.
During the Russo-Turkish War of 1877-78, Russian troops armed with mostly Berdan

Berdan rifle

The Berdan rifle is a Russian rifle created by famous American firearms expert and inventor Hiram Berdan in 1868. Standard issue in the Russian army from 1869-1891, the Berdan was replaced by the Mosin-Nagant rifle...

 single-shot rifles engaged Turks

Ottoman Empire

The Ottoman EmpireIt was usually referred to as the "Ottoman Empire", the "Turkish Empire", the "Ottoman Caliphate" or more commonly "Turkey" by its contemporaries...

 with Winchester

Winchester rifle

In common usage, Winchester rifle usually means any of the lever-action rifles manufactured by the Winchester Repeating Arms Company, though the company has also manufactured many rifles of other action types...

 repeating rifles resulting in heavy casualties.