A telescoped ammunition round comprises:a propellant charge having an axial cavity for supplying firing power to the ammunition round;a control tube means housed within the aft end of the axial cavity;a booster charge within the axial bore of the control tube, fireable in response to a primer means of the ammunition round in communication therewith; anda sabot/projectile assembly mounted within the axial cavity, its aft end extending into the control tube, wherein the sabot comprises an integral piston at its aft end to receive propulsive forces upon firing of the booster charge of the ammunition round.