So a while ago, A mate of mine who casts bullets for a living asked me about a custom sizing die, His Automatic sizer used Lee Sizing Dies. Essentially they were good for around 50,000 sizing's and sometimes there were under or oversize. So i made a prototype in carbide, final polish was done with 0.25 micron diamond paste. We found the ram pushed the projectiles easier then through the Lee dies.. We ended up changing his die holder over to a Lee APP Sizer Die. So I finished off Dies for most of the molds he has.. All things equal, He might have to check these to make sure they are still in spec at around 1 million sizings. Still have to finish off 357, 358, .40 and .500