after buying an RCBS gage for out of roundness (concentricity gage), I use the Lee Collet dies for everything. They consistantly produce necks under .002-.003. I had to get a redding small base body die for ,223 because of chamering problems. The lee die is only sizing the neck, and all calibers will start to chamber with difficulty as the brass grows and the shoulder moves forward with repeat firing. I set the shoulder back about every third loading with my 300 win mag. In my experience, I have found the lee dies to produce my most accurate rounds.