I finally bought a Detonics after wanting one for 20 years. It is a Mk I with a serial number in the 5000's. I am having feeding problems. The first or second shot out of the mag jams on the ramp in the frame. I even tried 230 gr roundball, same problem. The magazine is an aftermarket. I also tried a GI colt magazine with no change. Working the slide I observed that the nose of the bullet moves down when the slide first starts to strip it. Would lighter weight bullets help or do I need better magazines, or something else?