The United States adopted the Vickers gun as the Model 1915, but one of its uses was as an aircraft machine gun. Since it fired from a closed bolt, the design was easily fitted with synchronizer or interruptor gear systems to fire through the arc of a propeller. The French developed an incendiary loading of 11mm Gras for use on observation balloons, and the US adopted this variation as well, ordering 1700 of them from Colt in 1918 (in addition to 4300 aircraft Vickers guns in .30-06). The guns were fitted with muzzle protectors, recoil buffers, feed block booster springs, strengthened top cover latches, ventilated barrel jackets, and a new type of fusee spring adjustment system.
This example has been fitted with a Birkigt synchronizer, as would have been used on a SPAD XIII in American service.