Mac: mine is a regular P220 ST, also SA/DA. It, too, ran fine for the first 1000 rounds. In fact it ran fine for the first 5000 rounds. Now, the FTEx problems are driving me crazy. I mostly shoot reloads described above, but the same thing happens with Federal Hydrashok, WWB JHP, Speer Gold Dot, or MagTech FMJ. The brass appears to get pulled about half way out of the chamber and the extractor evidently slips off the cartridge rim. The slide continues to the rear and then tries to chamber the next round in the magazine but the next round jambs up against the partically extracted brass.