I use them for my .223 and 30.06. I like them. It goes fast if you chuck it in a drill. I use a flat bottomed cordless, and it can stand on it's own. I hold the drill sideways, so that I can use my thumb on my left hand to activate it, and the right hand to hold the cutter. Just chuck the shell holder end, and it makes pretty quick work. It helps if you get the other end with the ball on the end. Less cramping of the hand. You may notice the shell holder end seems to "wobble" when it's turning in the drill. Lee indicates that's normal. The cutter ends up "wobbling" with it, so the mouth ends up getting trimmed flush.
Dave