Abstract: Known cartridges have a cylindrical container part comprising an outlet nozzle arranged at the front, closed end and a piston inserted into the orifice in the rear end and movable in the longitudinal direction of the cartridge and intended for sealing the interior of the cartridge and ejecting the flowable material. The invention relates to such a piston. This is essentially in the form of a cylinder which is closed at one end and whose external diameter is at least as large as the internal diameter of the cylindrical container part. It is thus dimensioned so that, for closing the cartridge, it is pressed with a tight fit into the container part.