Could someone please tell me why I need to use a sizing button in my dies? I'm comparing Redding's Competition dies that don't use a sizing button and the next step down their Type S dies that do. I thought they were the same dies only without the micrometer on top. What’s the sense in using a bushing with the Type S dies if your going to pull the sizing button through the neck? I don't understand the need for the button in the first place. Is it because the neck wall thickness varies from different lots of cases? So if I don't use the button should I be turning all my necks first? Doesn't the button hurt the alignment of the neck?