Abstract: The pressure piston for a die-casting machine comprises a carrier formed with a crown having a central blind bore closed at its driving end and with an abutment ring. Surrounding the carrier and abutting the abutment ring is a piston skirt forming with the carrier an annular space through which passes a cooling medium. The skirt is held in position by a threaded clamping sleeve engaging a thread on the carrier on the side of the annular space remote from the abutment ring. By providing a thread of suitable length the carrier can accommodate skirts of various sizes. For this reason the axial extent of the carrier part between the abutment ring and the securing region for the clamping sleeve is less than the maximum but greater than the minimum length of the piston skirts.