The Russian government defaulted on the American contract for Mosin-Nagant rifles, and some of these American made rifles were issued to U.S. Many of these American-made rifles (about 300,000) were used for training purposes in the United States, who used some of the rifles in the early 1920s for National Guard and ROTC units. Remington and New England Westinghouse were commissioned to make Mosin-Nagant rifles during WWI to make up for a deficit in Russia. The Mosin-Nagant was even used by the United States. Many nations have also produced their own copies of the Mosin-Nagant. It has seen action in wars such as the Russo-Japanese war all the way to the Vietnam War and has been used by nations all over the world including Russia, China, Finland, Hungary, Poland and almost every nation that received aid from the Soviet Union. It was made famous for its use by the USSR in World War II. The Mosin-Nagant has been in service from 1892-1998 with about 37,000,000 being produced. This is easily the most common Mosin iteration, making the inclusion of Nagant's name all the more ironic. The reason for the name change was due in part because the improved Mosin M91/30 (1930) did away with many of the old features from Nagant's rifle, and the only surviving part from that design was the magazine spring. The rifle was formally adopted as 'Three-Line Rifle, Model 1891,' a reference to its caliber in the Russian cubit standard measurement series (1 line = 2.54mm or 1⁄10 of an inch), or later the Mosin Rifle - in Russian, 'Vintovka Mosina' - 'Rifle of Mosin'. The colliquial use of 'Mosin-Nagant' as a moniker for the rifle was brought about by western writings, as the rifle was never named this in Russia. In the end however, Mosin's rifle was chosen as the basis and Nagant's rifle lended features to improve what Mosin had. Through some deliberation, it was difficult to select a winner, as initial tests proved Nagant to be the winner, while additional ones turned things in favor of Mosin.

Three enterprising firearm inventors submitted their designs, being Leon Nagant with his 3.5-Line rifle, Sergei Mosin with his 3-Line design, and then a Captain Zinoviev with another 3-Line. In the late 1880s, the Russian Empire was in dire need of a new service rifle after having been equipped with Berdan single shot rifles for such a long time, which was a major contributor to heavy casualties in recent wars with the Turks, so a contest was announced for a rifle design to replace it. It is most commonly chambered in the 7.62×54mmR cartridge, which was designed alongside the rifle. The Mosin-Nagant is a Russian bolt-action, magazine fed rifle.

Mosin nagant grenade launcher