The Fusil Mitrailleur Modéle 1915 CSRG (Chauchat, Sutter, Ribeyrolles, Gladiator), more commonly known as simply the Chauchat ("sho-sha"), was a French light machine gun produced during World War I and extensively used by the French Army. Plagued by reliability issues, the Chauchat has since earned an infamous reputation as one of the worst machine guns to see military service.
The Chauchat was first conceived in 1903 by the Commission Technique de Versailles (CTV), headed by Colonel Louis Chauchat. Originally designed as a lightweight machine gun for use by bicycle troops, prototypes were constructed in 1910 by Ateliers de Puteaux and tested by the French Army throughout the proceeding years. By the time World War I broke out in 1914, the Chauchat was still in prototype stages and no decision had been made as to whether to adopt it. The CTV hurriedly pressed the French Army to accept the weapon into service, and it was finally adopted as the Mle 1915 in July 1915.
Production of the Chauchat was allocated to Établissements de Cycles Gladiator. The company, which before the war primarily produced bicycles, lacked experience in manufacturing small arms and as a consequence the quality of their machine gun produce was poor. Additional components were produced to a higher standard by Société Industrielle d'Armement (SIDARME).
For all its faults, however, the Chauchat was a pioneering example of the light machine gun concept. It was used until 1945, where it was completely replaced by the FM 24/29.
An aircraft variant known as the Chauchat-Sutter CS 1913 also existed. It had an overhead magazine and an alloy pistol grip section and stock.
The Chauchat used a long-recoil system, similar to the Remington Model 8 and the M1941 Johnson, where the barrel would move back a short distance every time the gun fired. The Chauchats had a very odd-looking magazine that held 20 rounds; this was one of the main sources of problems for said weapon. The Chauchat magazines had openings on each side, allowing the gunner or loader to see how much ammunition was left. However, this came at a cost. When the Chauchats were used in trench warfare, dirt usually got into the openings on the side of the magazine, jamming up the gun and rendering it useless.