Abstract: A projectile firing apparatus having a barrel (40) with a forwardly located exitaperture and an inwardly extending circumferential ledge (50), and two projectiles (41a, b), each having a penetrator (42a, b) and a sabot assembly having at least two sabot parts shaped so as to surround at least a portion of a respective penetrator (42a, b), the sabot assembly having an outer diameter smaller than the inner diameter of the barrel (40); and propellant (48a) located in the barrel between the projectiles (41a, b) and propellant (48b) located in the barrel (40) rearward of the rearward projectile (41b); and a pusher-plug (44b) located rearwardly of rearward projectile (41b) and forward of most rearward propellant (48b), the pusher-plug (44b) located against the circumferential ledge (50) wherein as a result of the expansion of gases resulting from ignition of the forwardly propellant (48a), the pusher-plug (44b) is forced against the ledge (50) to form a seal to the rearward movement of gases past the pusher-plug (4