Abstract: A device for perforating or cutting a target made of metal or other materials by means of a plasma jet. The device includes a cast grain of plasma producing pyrotechnic material that is coated over a major portion of its exterior surface with a combustion inhibiting layer. The coated grain is enclosed within an elongate hollow housing provided with closure plates at both ends thereof, with one of the plates having a nozzle opening that is substantially coextensive with a longitudinal recess formed within the grain so that the plasma jet produced by the incendiary reaction of the grain is directed out through the nozzle opening for impingement upon the target.