A syringe (114) is received with a housing, the syringe having a bore terminating at a forward end in a hypodermic needle (118) and at a rearward end in a flared opening (210) in which a bung (134a) having a bore (206) surrounded by a skirt (208) is inserted. A drive element (134) has a forward end consisting of a substantially flat annular region (200) that bears upon the skirt of the bung and surrounds a conical middle region (202) that is received in the bore (206) of the bung. An actuator advances the drive element (134) so as to advance the bung and discharge the contents of the syringe through the needle (118). The opening (210) in the rear of the glass syringe is flared by being provided with a radius. The combination of the radius at the opening and the projecting conical middle region of the drive element allows misalignments of the two to be managed during automated assembly.
