A system for accelerating an armature to launch a projectile by injecting liquid aluminum between the armature and a pair of electrically conductive rails. A system for accelerating an armature by injecting liquid metal between the armature a plurality of electrically conductive rails and collecting the liquid metal. The liquid metal or liquid aluminum can comprise solid particles. A railgun structure with mechanical guide rails. A railgun structure with a film stack of alternating copper and nickel layers. An armature with guide rail supports. A method of using the system by placing liquid metal in the armature, placing the armature between conductive rails, and applying an electric current to the rails.