I was messing around after thoroughly cleaning my M-9 yesterday, trying to figure out why it would leave the empty half sticking out of the chamber when it was trying to double feed. I had the barrel out and dropped in an already fired empty. Lo and behold I had to push it in fairly hard the last .7 inches. Took another one... same thing. Hmm.. jammed them in and they were pretty tough to get out. So I popped the primer out of an empty with a pin punch and stuck a screw in the primer pocket. This gave me a shell with a screw head poking out. I put a thin coat of JB bore paste on the muzzle end of the shell and pushed it in the barrel. I then took my weak battery drill and turned it for about 10 seconds, pulled it out, wiped it off, put more JB bore paste until it would seat with a light push. Probably a total of 25 seconds of slow speed turning. This polished the chamber pretty well and judging from the empty with the screw in it, it removed a very TINY amount of chamber near the mouth of the shell. I cleaned the crap out of the barrel again, then tried the empties. They fit with a much lighter push. Took it to the range today and put 50 rounds through it. I couldn't make it jam! Victory! Hope this helps someone else out there.