A device and method to accelerate solid metal slugs to high speeds. In one embodiment, a large electric current is passed through an outer cylindrical metal tube enclosing in part a metal slug, a central electrode, and a conducting tail coupled at opposite ends to the. metal slug and the central electrode. Electromagnetic forces accelerate the metal slug to a point high enough to mechanically separate the conducting tail. On separation, a plasma is generated by the passage of electric current though a gas produced by vaporization of the conducting tail and nearby materials. An insulator enclosed within the tube prevents the plasma from shorting to the outer tube until the current flow has produced a sufficient magnetic field to contain the plasma. The metal slug is then accelerated to high speed by a combination of electromagnetic forces and mechanical pressure from the hot gas through which the electric current is passing.