Probably late to the party but just in case anyone new comes along and needs some help with their 500JRH loading, I use the RCBS 500 S&W Mag/Spec carbide die set(RCBS #: 23812). Did not have to cut down the seat/crimp die since the die can be used with the 500 S&W Special. I purchased an additional Seat/Crimp die (RCBS #: 23838) and use it on my Dillon 550b to separate the seating from the crimping. This setup work very well for my needs.
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