Abiel Revelli designed this machine gun in 1908, and gave the production rights to FIAT, who marketed the weapon domestically and internationally. It was trialed by the US Army in 1911 but not accepted, and was submitted for testing by the Italian Army, who initially showed little interest, as they were in the process of evaluating the Perino Model 1908. However, when the war broke out in 1914 and the Army had still not come to a decision regarding the Perino, FIAT decided to set up production for the FIAT-Revelli machine gun regardless. The Army, in desperate need of machine guns, bought thousands of FIAT-Revellis in 1915 and fielded them in large numbers against the Austro-Hungarians.
The FIAT-Revelli was a delayed blowback machine gun with an unusual feed system. The cage-like magazines were compartmented into ten 5-round rows. After the lowermost row was depleted, the next row would take its place and feed into the gun. In order for this process to function without stoppages, the bullets needed to be lubricated.
The bolt was connected to the barrel via a rotating wedge. Upon firing, the bolt and barrel would recoil together for about half an inch, until they reached a stop and the wedge would rotate, forcing the barrel back to its original position. When the barrel separated from the bolt, the gas pressure that had built up upon firing would be released and push the bolt back to the return spring, whereupon it would be pushed back towards the chamber and reconnect with the barrel.