I think I'm losing my marbles - this seems like an impossible task. I tried again this morning - I've completely removed the Hornady die. Then made 20 test rounds of a COL from 1.100 to a ludicrous 0.990 I've tried all of the with different crimp taper depths - all of them dont seat properly. I put a marker around the brass and it rubs off on all of them at the mouth. It's a no go with the RCBS die. How can it be this difficult? :banghead: At this stage I think I might just so and buy some new dies and get some FMJ's while I'm at it.