The Chauchat-Ribeyrolles 1918 submachine gun is a French prototype automatic weapon. In 1917, the French Army adopted the Mle. 1917 semi-automatic rifle made by Ribeyrolles, Sutter and Chauchat (RSC), who already developed the "Chauchat" Mle. 1915 LMG. In 1918, they presented a "pistolet-mitrailleur" (submachine gun), meant to be used for close-range protection for the French tank crews. The weapon is based on the RSC Mle. 1917 semi-automatic rifle mechanism. The first trials used a Mannlicher–Berthier clip holding eight cartridges. The trials continued until 1919 with a weapon using the same magazine as the Chauchat. The results were satisfactory but the weapon was too powerful for the intended self-protection use. A mix of standard and tracer bullets was planned to be used to assist in aiming.