I find the system used on my Krieghoff O/U DR's ideal. All you need to do to convert extractors to ejectors and vice versa is to remove the retaining screw and insert or remove the coil spring which activates the ejectors, and although I am less than happy about the idea of using rimless cases in DR's, both sets of barrels, in calibers .458 WM and .375 H&H, have always functioned flawlessly. That said, my more recently acquired Krieghoffs all use rimmed cases (9.3X74R, .500 NE and 8X75RS).