If you have the means, this was pretty easy. I used nylon as the case bed, since it was the slickest thing I could find in the shop. I tried polished aluminum, but that had lots of drag. Steel was a little better. But nothing beat the nylon. And its a wiz to machine.

Just bore a 90deg V down the length. For rimmed case's, dont forget to cut a small channel so the rim is free floating. And cut yourself a small backstop with the same bit. Bolt it down, or glue it down.
Slap on a magnet, some rod and a gauge, and it works great.
I can press my finger on the front of the case, and the rear of the case and get no movement. Which is why I built one. I used one a friend of mine had bought, and it just had too much movement subject to the users finger placement (kinda like a 'rocking' movement).

One interesting note. I had a few bullets that gauged about .008-.011 out. I stuck them in the Lee factory crimp die, and it took about .003 out of them each time. Unturned cases.
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