Have you tried ejecting mtys but with the hammer down? You could try it with the hammer gently lowered and then try it with mtys with the hammer dropped using the trigger. See how the firing pin extension moves. Another experiment would be to fire a round but thumb cock the hammer not disturbing things and then eject the mty as usual. See what that does. Try to eliminate contributing factors one at a time, recoil, the hammer, extractor, firing pin extension, ammo, etc.