oldmanriver,Raimey
9.3x65 cases can be made from 9.3x74R, by "swaging" the head to size,turn the rim to size and trim to length. The Collath case is shown in Cartridges of the World(often mistaken)as having a .443" head diameter.In my experience,Norma 9.3x74R often measures .460" at the head.This leaves a difference of .017",which I would do with two .010" reductions to account for "springback".If this didn't prove necessary,I would open up the final die by one or two thousanths. Sounds like a fun project-have at it.
Mike
