A capsule assembly (4) for an endograft introducer is disclosed. The assembly (4) comprises: a capsule (5) and a capsule plug (100). The capsule (5) has a cavity for receiving an end of a stent graft and a capsule wall (6) terminating in a distal end. The capsule plug (6) comprises: a tip portion having a lead-in surface and an abutment surface and a tail portion having an external surface engagable with an inside surface of the capsule wall. The capsule (5) is slidably movable with respect to the capsule plug (6) from a first position in which the distal end (7) of the capsule wall (6) surrounds an opening into the cavity to a second position in which the distal end (7) of the capsule wall (6) is positioned proximally with respect to the abutment surface, whereby movement of the tip portion into the capsule (5) is resisted by abutment between the distal end of the capsule wall (6) and the abutment surface.
