An injection device is described. A syringe 114 is received within a housing, the syringe having a bore terminating at a forward end in a hypodermic needle 1 18 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 208 of the bung 134a and surrounds a conical middle region 202 that is received in the bore 206 of the bung 134a. An actuator advances the drive element 134 so as to advance the bung 134a and discharge the contents of the syringe through the needle 1 18. 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 210 and the projecting conical middle region 202 of the drive element allows misalignments of the two to be managed during automated assembly. This is because the conical middle region 202 either pass straight into the opening 210 of the syringe, or contact the radius, which guides them towards the centre of the syringe bore. The radius and the substantially flat annular region 200 and the central conical portion 202 of the drive element 134 are so shaped and dimensioned that axial misalignment between the syringe 1 14 and the drive element 134 during assembly of the injection device are corrected by, firstly, the conical middle region 202 of the drive element 134 riding up the radius to a point at which, secondly, the substantially flat annular region 200 also makes contact with and rides up the radius, to align the drive element 134 in the bore of the syringe 1 14.
