The Royal Cannon Foundry 47mm anti-tank gun Model 1931 (, abbreviated to C.47 F.R.C. Mod.31) was an artillery piece developed in 1931 for the Belgian army which saw widespread service in the Battle of Belgium in 1940. It was colloquially known as the "'Quat'sept" (Forty-seven) by the soldiers that used it. It was developed by the firm F.R.C., the Herstal-based Fonderie Royale des Canons, not to be confused with the French F.R.C.