An injection device (110) comprises a housing (112) adapted to receive a syringe (116) having a discharge nozzle (118) and dispensing piston (114) movable in the syringe to expel the contents of the syringe through the discharge nozzle. There is also a drive (130) adapted to act on the syringe to advance it from a retracted position in which the discharge nozzle is contained within the housing to an extended position in which the discharge nozzle extends from housing. A drive coupling (134) extends from the drive to the dispensing piston of the syringe so as to transfer movement of the drive to the piston. The drive coupling comprises a fixed-length drive-coupling and an interchangeable drive coupling. There is also a method of manufacturing an injection device by assembling a first sub-assembly (210) and second sub-assembly (220).
