Buckstix,
Corbin makes very good dies, but are very expensive. If you don't have a lathe, you can have someone make a simple die that will screw into your press(7/8"-14 tpi). Corbin may have a "ring" sizing die, that is a die body that uses interchangeable
rings of different IDs. Jacketed bullets shouldn't be sized more than .005"( note .323" to .318",meets this "rule of thumb"). With type die, to change diameters, it is only necessary to make a simple ring with an OD to fit the die, and with an ID of the desired bullet diameter. This can be made, relieved at the corner, and highly polished, by anyone with a lathe.
Mike