Like many others, my M9 was plagued by faulty extraction periodically. I managed to get a 1911 plunger spring and cut it to size to fit in with the original extractor spring. Boy - talk about a PITA to get that spring assembly back in there without losing an eye! I haven't had a chance to go to the range until this past weekend, but it looks like it did the trick. There's still the occasional piece of brass which will bounce off your noggin, but no jams this time.