These things are NOTORIOUS for failure to feed. Doesn't like those first few rounds out of the mag, does it? On the feed ramp, I true up a brightboy in the Dremel to a radiused end and remove the tool marks (George is right, watch that angle!). Then, use a felt bob with some matchless compound and really get 'er bright & smooth. Stone the breech face super smooth. Radius & polish the leading edge of the extractor (I can't show you how to do this here, but use the same common sense you would on a 1911 or similar extractor. Make sure the extractor moves really smooth in the slide - polish the sides glass smooth. Really slicking up that loaded chamber indicator is a good idea, too. These little stinkers are really rough inside, so detail strip the piece and go hunting for burrs. Use a smooth mill file and remove those horrible broach marks from the outside of the barrel housing on the frame, then polish it bright(this can't hurt, and it looks better bright anyway). Polish your mag followers super smooth, and grind a radius on the front of the mags - this helps those first few "nose-divers" clear the lip of the mag and get on their way up the feed ramp. Also, stay away from that "UMC" garbage that's on sale at K-Mart!