9.3,

This is not my own design, I had a plastic BPI roll crimper which got buggered eventually luckily before it died I had a friend who makes precision die components make one for me in stainless steel with a few changes,it has two concave teeth diagonally opposite each other which was done on an EDM. I will ask him for the drawing and post it here for anyone who wishes to make one, works very well on both plastic and paper and makes a nice, tight and uniform crimp, I did have to break it in a bit with some Colgate toothpowder and light machine oil and a few dozen fired plastic hulls as occasionally it would grab the plastic when it was new, it doesn't happen anymore. I also managed to win an auction for a Lyman 12ga roll crimper for shot and RB loads, it does a beautiful job on paper and plastic.