Medical device delivery systems, and related methods and components, are disclosed. In some embodiments, an implantable medical endoprosthesis delivery system includes a catheter, a sheath at least partially surrounding the catheter, and a tip coupled to a distal end portion of the catheter. The tip can cooperate with a distal end surface of the sheath to form a gap therebetween so that there is fluid communication between an interior region of the sheath and an exterior region of the sheath.