The OG-43, designed by Giovanni Oliani in the factory based in Cremona named Società Anonima Revelli Manifattura Armiguerra, was an advanced submachine gun, designed for compactness and ease of mass production.

It is part of a family of weapons produced under emergency measures during the time of the Italian Social Republic, which include the TZ-45 machine gun, FNAB-43 and Isotta Fraschini.

The bulk of the L-shaped bolt, along with the recoil spring, was housed in a cylinder directly above the barrel, which helped reduce muzzle climb when firing.

The weapon was short-recoil blowback operated, and fired from an open bolt in both automatic and semi-automatic mode.

It adopts the traditional wooden stock hinged to the pistol grip, positioned behind the trigger and the magazine well.