The Redding dual-ring carbide dies are for the long straight-walled revolver calibers, I believe. I seriously looked at getting one of those but the price put me off. I then figured out how I could do the same thing (in two steps) using the Lee carbide crimp die, with the crimp insert removed. I full-length size using the FCD, then use a regular sizing die to resize just the area where the bullet seats. A lot more work than is necessary, I know, but I end up working the brass a lot less and hopefully that will make my 460 S&W brass last longer.