I picked up a little widget that holds a Wilson chamfer tool and lets you chuck it in a drill. Best $20 I ever spent. Clamp the drill in the bench vise, lock the trigger back and go to town! I found out it's best to wear gloves though, especially when chamfering primer pockets. I got a nice little .223 caliber cut on my finger when the tool grabbed a case for a second! <laughs>