The Beretta Model 1918 (Italian: Moschetto Automatico Modello 1918, or MAB 18) was an Italian submachine gun designed and manufactured by Beretta in 1918. It is considered one of the first practical submachine guns in history, having been made and used in combat sooner than the German Bergmann MP 18 by a few months.
In 1917, the Italian Army commissioned Beretta to develop a single-barreled infantry carbine version of the twin-barreled Villar Perosa submachine gun, which they felt was a useful trench-clearing weapon but impractical in its then-current state. Beretta placed Tullio Marengoni in charge of the project and the resultant weapon was the M1918. It was adopted by the Italian Army in January 1918 and issued to Arditi troops. World War I ended the same year and the M1918 saw little action afterward. In 1930, Beretta converted many M1918s into semi-automatic carbines known as the M1918/30 for the Italian police.
When Italy invaded Ethiopia in 1935, some M1918s were still in military service and saw limited use. These guns would continue to be used into World War II, but the M1918 was officially replaced by the Beretta Model 38 in 1938. After the war, any M1918s left were retracted from military issue.
The M1918 is a delayed blowback submachine gun; internally it is identical to the Villar Perosa. The only major internal difference was the redesign of the trigger mechanism. It had no selective fire capability and fired exclusively in full-auto.
Externally the M1918's furniture was taken from parts of existing Italian military rifles, such as the Vetterli-Vitali. The M1918's folding bayonet was taken from the Carcano rifle. Relatively few of the components used to make the M1918 were new parts.
In 1930, Beretta re-purposed many surplus M1918s into semi-automatic carbines known as the M1918/30. This variant used a fixed firing pin and fired from a closed bolt. The cocking was changed from a slot on the right side of the receiver to a retractable ring housed in the rear end of the body. The M1918/30 did not feed from the top; the magazine feed was relocated to the bottom of the receiver. The magazine capacity was 15 rounds. It was intended as a police weapon and was sold to the Italian and Argentine police forces.