Electromagnetic launcher with high repetition rate switch

An electromagnetic projectile launcher is provided with a cartridge-type switch for commutating current from a high current source to a pair of generally parallel conductive rails. A conductive cartridge switch in sliding electrical contact with the rails at the breech end includes a pressure chamber and aperture for receiving a projectile. An increase in pressure in the pressure chamber forces the projectile forward while forcing the cartridge rearward. Current is commutated from the cartridge to a conductive armature which subsequently propels a projectile along the conductive rails.