The present disclosure relates to an injection device for delivery of a liquid medicament including a housing, a cartridge having a tubular shaped barrel filled with a liquid medicament and sealed in a proximal direction by a piston displaceably arranged in the barrel, and a drive mechanism having a piston rod to advance in a distal direction against a proximally facing surface of the piston of the cartridge. The drive mechanism is configured to advance the piston rod in the distal direction by a distance z1 to dispense a reference volume V1 of the medicament when operably engaged with a reference cartridge having a reference diameter D1, and, the cartridge has a diameter D2 smaller than the reference diameter D1 to dispense a volume V2 of the medicament smaller than the reference volume V1 when the piston rod advances in distal direction by the distance z1.
