Lee will also make a custom factory collet crimp die for you. You need to send them a sample case with seated bullet and drill a large hole in the side of the case-base to show (customs?), it's not a loaded round. Lee will return these with the new die. I did so with a 5.6 SE vom Hofe several years ago. I'd email them first to make sure they still offer this service, but Colin Greenwood refers to this option in his book on rook rifles. Being heeled bullets, they can't be readily crimped in the normal way as the bullet diameter precludes it.