A cartridge feed system for an automatic gun comprising a drum magazine possessing a number of chambers, the drum magazine being rotatably mounted about a drum shaft connected with the gun mount and incrementally or step-wise drivable. A first feed device is provided which moves the cartridges out of a respective chamber of the drum magazine and such first feed device is arranged stationarily externally of the drum magazine. A storage is disposed between the drum magazine and the gun and possesses two channels. The storage with the channels is arranged to be displaceable and each channel selectively can be shifted or displaced into a work position and into a rest position for the selective firing of different types of ammunition. A second feed device is provided which moves the cartridges out of the storage and delivers such to the gun, while the drum magazine is further rotated through one indexing step.