An apparatus includes a propellant chamber, an expansion chamber, an exit chamber comprising a port providing fluid communication outside the apparatus, and a longitudinal acceleration chamber. The longitudinal acceleration chamber includes a first end in fluid communication with the propellant chamber, a second end in fluid communication with the expansion chamber, and a longitudinal axis between the first end and the second end. An acceleration mass is slidably contained in the acceleration chamber. The acceleration chamber includes a propellant side between the propellant chamber and the acceleration mass, and a target side between the acceleration mass and the expansion chamber. A transfer piston is slidably positioned between the expansion chamber and the exit chamber. The transfer piston includes a first end projecting into the expansion chamber and aligned with the longitudinal axis of the acceleration chamber, and a second end projecting into the exit chamber.