Abstract: A cartridge magazine for holding cartridges for feeding to the barrel of an explosion driven fastener setting tool comprises an elongated flat flexible strip or band preferably made of an inexpensive material such as plastic. The strip includes a plurality of stepped projections defining cartridge holding recesses arranged at equally spaced locations along the strip and lateral recesses for advancement. Each cartridge holding recess is defined by a stepped projection extending upwardly from the strip which on its exterior is stepped inwardly in a direction toward the tip of the cartridge. The angular taper of each of the outside walls of this portion on the cartridge magazine is slightly less than one cone angle of the cartridge chamber of a gun barrel with which it is to be employed, so that there will be more than one sealing point between the projections and the inner wall of the cartridge chamber.