Beretta M1918

The Moschetto Automatico Revelli-Beretta Mod. 1915 (commonly known as the Beretta Model 1918) was a self-loading carbine that entered service in 1918 with the Regio Esercito. Designed as a semi-automatic carbine, the weapon came with an overhead inserted magazine, an unconventional design based on the simplicity of allowing a spent round to be replaced using assistance from gravity. The gun was made from half of a Villar-Perosa aircraft submachine gun.
Like all weapons of the Villar Perosa family, including the O.V.P. submachine gun it was originally intended to fire a variant of the 9mm Glisenti cartridge, known as Glisenti M.915 "Per Mitragliatrici" ("For Machine-Guns"). This was a higher-velocity version of the standard Glisenti cartridge with an over-powder wad, designed to improve the penetration abilities of the weak base cartridge.