I am newly registered to the forum but have read and followed the discussions as a guest for some time. I signed in and am posting to bring to member's attention a serious yet easily prevented potential and as yet (I believe) unreported problem. After putting a small number of rounds through a new, cleaned and lubed MP9c, I unloaded and sat down on the porch to dryfire and finger my newest toy. On the second "snap", the trigger died. No reset, no snap. Opening the piece up I found the sear lifeless with no spring tension returning it to its proper orientation. The problem was found in the sear plunger/sear spring hole. A slight gouge in the side of the sear spring hole (under the sear and home to the sear spring and plunger) possibly combined with a bit of manufacturing debris, trapped the sear plunger with the spring compressed. This prevented the spring/plunger from properly tensioning the sear and resulted in a failure of the trigger to reset. The solution was to disassemble the rear block, flush then work the plunger free with a pick, clean up the hole then reassemble. My suggestion for preventative maintenance is to occasionally flush under the sear with a cleaner like Gun Scrubber. Regards, R