Responding to this request, the ingeneer Giovanni Oliani created an interesting "moschetto automatico" (automatic rifle), with a caliber of 9x19mm Parabellum. The prototype was produced by the company ARMAGUERRA of Cremona.
The prototypes and the tests were completed in 1944, so the new assault rifle received the name O(liani) G(iovanni) 44. This was the defintive assault smg that followed a previous prototype called OG43 (the OG43 vaguely inspired the Israelian UZI of 5 years later...).
The RSI war ministry asked the company to start a mass production, that, like many other Italian military productions of WW2, never started. However, a few specimens were produced towards the end of the war, and the foreplay for a larger production by the famous "Fabbrica d'Armi Beretta" had just started when the war finished.
This weapon, however, was an important "step forward" compared with s.machine-guns of the second World War; in fact the OG44 introduced a "slim frame" technology: that is, a configuration that has approximate a "L" shape influencing the weapon ballistics.
During the shot, the weight of the longest part of the weapon "moves" toward the bar, so as to balance the weapon during the burst. This great technique was later copied by famous sub-machine guns such as the Franchi LF57 and the WALTHER MP-L.
The OG44 was a blowback weapon with Selective Fire (with a cycle of 500 rounds per minute), and had ventilation holes along the barrel with a diameter of 1.5 mm.
It could be set with a fixed wooden stock or a retractile metallic one.
It used loaders of 25 shots, but to accelerate the use by the RSI armed forces it was also equipped with the common loaders for Beretta MAB 38, with 20, 30 and 40 shots.
The OG44 had a barrel 292 mm long, was 788 mm long itself, and had a weight of 3.5 kg with the wooden stock and without loader.