In 1971 Australians Barber and Marshall railgun-accelerated a small projectile to 7 km/s; spawning a new era of electric hypervelocity launchers for weapons, space launch, and impact fusion. Among electromagnetic candidates only the railgun achieves multi-kilogee accelerations needed for short-barrel guns. However, input currents of Mega-to-Giga-amperes are required. Also in the conventional railgun half of the input energy stays behind as residual field. Yet further, restrike effects in the plasma "armature" presently limit launch speeds to6 km/s. The GRAIL railgun offers to provide (proprietary) solutions to these problems as well as to eliminate muzzle flash.
