I've been cutting em down since 2001 when Bond and I started doing it. With a Lyman Universal Trimmer, Power adapter and a carbide cutter I can do between 200-250 per hour (I hit the blades with water or silicone dry lube every 20 or so to keep it cool and sharp). I am able to keep tolerance at about .001. I cut them then throw em in the tumbler for a few hours to de-burr, any that still have burrs get a quick de-burr with hand tool.