The Mosin-Nagant rifle was adopted by Russia in 1891 after trials of several repeating bolt actions. It fires the 7.62x54r cartridge and is a combination of designs by Russian Sergei Mosin and Belgian Leon Nagant whose primary contribution was the feed system. The official designation is “3 line rifle, model 1891”. A “line” is a unit of measure equal to 1/10th of an inch. Production of the Model 1891 took place at the Russian arsenals at Izhevsk, Tula, and Sestroryetsk. Due to a slow start in domestic production a contract was issued to the French arms company Chatellerault who built around 500,000 M91s.