Injection device including a casing, a syringe carrier located within a proximal end of the casing and being movable along a longitudinal axis of the device between a stowed position and a needle insertion position, a drive assembly located within a distal end of the casing and being movable by an insertion driver in order to move the syringe carrier and a loaded syringe from a stowed position to a needle insertion position; a first formation fixed relative to the casing and a second formation fixed relative to an insertion tube of the drive assembly, the first and second formations defining a plurality of stop positions for the insertion tube relative to the casing, spaced along the direction of said longitudinal axis, to prevent significant rearward movement of the insertion tube along said axis when a plunger of a firing cartridge is released from a reaction assembly of the cartridge.