Easy. In fact, I did one last week. Chuck up on a split dowel or aluminum rod in the drill press, hold the die in the vise making sure it is straight up and down. Wrap some 320 grit sandpaper on the dowel to the right diameter, set the spindle pretty fast, and have at it. Up and down fast, check the bore every 50 strokes or so with guage pins, and when the one you want will just BARELY go, you're done. This is pretty much SOP for me and Lee sizers since they come from the factory so rough on the bore that they're all but unusable. Once you polish them out to a good finish they're so much nicer to use and don't lead up. Making a new hardened pusher real close to the bore diameter helps too and prevents finning or rolling the bullet over on the edges.
