I really want to like my 550, but I just keep having problems with it. Maybe I am just too picky, as I have never had issues with my reloads before, 1 FTF ever, never a squib, never a double charge, etc., but I seem to have problem after problem getting my 550 to run how I want it to/think it should. Short rant over, now my issue. Ultimately the problem is the shell plate is leaving a burr on the rim of the casing, just large enough to prevent the case from fitting a drop in case/cartridge gauge. Through trial and error, I have determined that the majority of the burr is created when pulling the case out of the sizing die. (Lee Carbide Die) Seating the primer also leaves a small burr, though this alone is not large enough to prevent the cartridge from fitting the chamber gauge. My immediate though is that I had the Die adjusted poorly, in too deep, but after several adjustments and a few more garbage cases, this is not the issue. Next I switched dies to ensure that was not the issue. I followed by adjusting the tension on the shell plate both looser and tighter to see if it was pulling unevenly on the case rim. And I also did check to make sure that I was not an idiot and had the wrong shell plate installed. To me, it simply appears that the fit of the shell plate is too lose, and that it is not grabbing enough of the rim when pulling the case free, and is rounding off the square corner of the case rim, which is keeping it from fitting the gauge. Is there any other explanation here? Shell plate does not appear overly worn, or warped. This issue is present on about 50% of all my 9mm loads off the press, and does not seem to affect feeding or ejection, though it is obviously detrimental to case life, and maybe extractor wear. Ideas? I couldn't get my phone camera to focus on the burr on the rim, here is a pic of the complete cartridge not quite fitting the gauge.