The Scotti Model X was an experimental Italian semiauto design from the 30s. It was introduced in 1934 with a total of 250 made for trials, but the name suggests that it was designed in 1932 or early 1933. The Italian military often dated items based on a Fascist calendar beginning in October 1922 (when the Fascist government took power in Italy). So, a rifle marked XIV would have been made in 1936 (1922 + 14). In the case of the Scotti, the “X” have nothing to do with experimental, it’s just a date.
Mechanically, the Scotti is basically a straight-pull bolt action with a gas piston added below the barrel. The Scotti uses standard Carcano clips, and is chambered for the 6.5mm Carcano cartridge. These rifles did see some limited field use out of necessity, but were not formally adopted by the Italian military.
We happened on this Scotti Model X at a gun show, and the owner was kind enough to let us photograph it. (download this gallery in high resolution)