10 mm

roll crimp?

taper crimp?

and why would you choose one over the other?

looking for suggestions

Taper crimp, ever so lightly. You will need a taper crimp, since it head spaces off the case mouth. I put enough crimp to close up the bell opening from bullet seating, and hold the bullet in place.

What Chad says. The case should be resized enough to provide the necessary tension on the bullet and the taper crimp should basically just remove the flare from the case mouth.

Well said by Chad. That's exactly what has worked best for me, even with max listed loads

^^^^ all the above

thank you all

taper it is