In the 1930s, the Italian military (like all major military forces at the time) was investigating options for a semiautomatic service rifle. Beretta's Tulio Marengoni developed one such rifle, and submitted it in two forms.
The first version of the rifle was produced in 1931, chambered for the then-standard 6.5x52mm Carcano cartridge. It was a short-recoil action with a rotating bolt, and fed from standard 6-round Carcano en bloc clips.
The second version was produced in 1937, after the Italian military had adopted the 7.35mm cartridge. The 1937 version was made slightly shorter and had a simple fixed rear sight (both changes similar to what would be made for the M38 Carcano rifles). The 1937 Beretta also used a new magazine system, fed by stripper clip. The capacity it not clearly known; probably either 9 or 10 rounds (and the type of clip used is also not known). Finally, the 1937 rifle included a locking mechanism that could be used to prevent the barrel from recoiling, and thus turn the rifle into a manually-operated one instead of a self-loader.
The internal mechanism was quite novel. Perhaps too novel, as neither rifle was adopted, nor were either produced in any substantial quantity. Ultimately the Armaguerra model 1939 was the winner of the extended trials, but World War II interrupted any plans to put it into mass production.