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