The Villar Perosa was a rather odd weapon developed by noted designer Revelli in Italy in 1914 and adopted into service in 1915. It was a pair of open-bolt submachine guns (predating shoulder-fired submachine gun designs, interestingly) mounted side by side one a set of spade grips. It had an extremely high rate of fire, and was initially intended for use on aircraft, against other aircraft. However, it fired the rather anemic 9mm Glisenti cartridge, and was thoroughly ineffective in the AA role. It was then adapted to serve as a ground machine gun. Of course, it also suffered from having no practical grip or stock, and could only really be used from a mount. Again, not so practical.
In 1918, Beretta started separating the M1915 Villar Perosas into their component halves, adding stocks, sights, and more conventional triggers, and they were used by the Italian military as conventional submachine guns. The modification is probably the reason why so few original Villar Perosa guns remain in existence.
Anyway, the point of this information is to introduce the original Villar Perosa M1915 manual we now have available on the Original Manuals page in the Vault. If you have a couple extra SMG parts kits you don’t know what to do with, perhaps you could build a reproduction Villar Perosa?