I use a straight 6mm-223 from Hornady, it is the same as a 6x45. On the Redding bushing die if your handy and careful you can open the top of the die, it will get expensive if you screw it up though. I did that with a 204 Ruger Type S FL bushing die and load 22-204, 6mm-204 and 25-204. with it just swapping out expander balls, bushings and changing out the stem to handle the larger threads on the bigger expander balls.