A pusher plate assembly for launching a projectile includes a pusher plate, a pressure seal circumferentially extending about the pusher plate, a cage extending from an aft side of the pusher plate, and a plurality of propellant portions disposed in the cage. A projectile system includes a launching tube, a projectile disposed in the launching tube, a pusher plate assembly disposed between an aft end of the projectile and the launching tube, a fuze, a charge igniter operatively associated with the fuze and the plurality of propellant portions, and a retainer disposed within the launching tube proximate a mouth of the launching tube. The pusher plate assembly includes a pusher plate, a pressure seal circumferentially extending about the pusher plate to seal an annulus between the pusher plate and the launching tube, a cage extending from an aft side of the pusher plate, and a plurality of propellant portions disposed in the cage.