I use ordinary Hornady 8x57 FL dies, but I got an extra factory expander button and turned it down a little in a lathe, so that the same die set will do for both .318" and .323" Just looking at those 2 numbers, I guess it was 5-thou taken off. So long as the sized case neck holds the bullet firmly, and a new bullet will also slide in and out of a fired neck, you've got it right.
Hornady use a sliding bullet sleeve in the seating die. The .318" bullets seem to seat straight even though they're undersize, but I also use a Hornady device that straightens the bullets besides so that they have just 1 or 2-thou runout.
The bore on my 8x57JR Drilling is certainly worn, but it still shoots well. I used Norma 8x57RS brass and RWS 196 grain .318" bullets.
