A drum magazine is a type of firearm magazine that is cylindrical in shape, similar to a drum. Instead of rounds being stored flat, as in a more common box magazine, rounds in a drum magazine are stored in a spiral around the center of the magazine, facing the direction of the barrel. Probably the first drum magazine to be patented was the one by Salloum Dahdah in 1862. A precursor to the drum magazine was the Accles drum, used for Gatling guns. The first true drum magazine was invented between 1908 and 1915 for the Farquhar-Hill Rifle, the patent for which can be found here.