I have a Lee size die .339 that I am trying to open up to .351. Using a dowel rod plus both wet/dry paper & emery cloth, it is taking forever! I have been using 220 paper and coarse emery cloth chucked up in my drill for four hours plus and have only opened it up .003 at the most. I am on my second 20v battery charge too. Reading previous posts about this sounds like a piece of cake but its slow going for me. All I can think of to speed things up would be to heat up the die cherry red and let cool, to take out the hardness. I have the die chucked up in a Lee turret and mounted in a vise to handle the heat from grinding. After all of this, I ran a bullet through the die and it measures .341 at this point. I guess I need some coaching. /Chris