Here's the reply I got from the Redding Tech. when I posed a similar question concerning .357 Max dies.
Hi William.
Thank you for your interest in Redding Reloading Equipment. We offer die sets for the 357 MAXIMUM in our custom series, but you can reload the cartridge just fine with any properly adjusted 38/357 die set. I’ve loaded for years for my two 357 MAXIMUM firearms (TC Contender & H&R Ultra Rifle) this way.
Regards,
Patrick T. Ryan
Redding Reloading Equipment
1089 Starr Road
Cortland, NY 13045
607-753-3331
FAX 607-756-8445
Bill