In late 1917, Cpt. Amerigo Cei-Rigotti -
better known for his early automatic rifle - designed a single-barreled
carbine adaptation of the Villar Perosa submachine gun. The relevant
patent was filed on January 2nd 1918 and it was probably intended to be
entered into the contemporary Italian SMG trials. The records are few and
far between, however, so there is little surviving information on this
gun. The rate of fire is recorded as having been 800rpm. In any case, it
was not successful and no prototypes are known to exist.