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.

• Ribeyrolles 1918 automatic carbine
• M231 Firing Port Weapon

• [1] has info from Jean Huon (2007). Les pistolets mitrailleurs français. Editions Crépin-Leblond. ISBN 978-2-7030-0300-7. cf. [2]
• Ribeyrolles 1917 at securityarms.com^{[unreliable source?]}

• Jean Huon (2007). Les pistolets mitrailleurs français. Editions Crépin-Leblond. ISBN 978-2-7030-0300-7.

• pictures (2nd and 3rd)