The Villar Perosa was designed as a portable double barrel machine gun firing a 9mm round. In practice the machine gun consisted of two independent coupled weapons, each with its own barrel firing mechanism and separate 25 round magazine. As it was originally designed to be operated from airplanes it had a high rate of fire of over 1,500 rounds per minute. However, in practice the 9mm munition was not sufficiently powerful to shoot down aircraft which had become ever more resistant over the course of the war, and in addition the range was inadequate.
Instead the Villar Perosa began to be issued to ground troops. Between May and November 1916 a section was assigned to each infantry battalion of the Italian army and from May 1917 the number of sections was increased to 3 per battalion. The weapon was first used at the 12th Battle of Isonzo.