I run SSA (OLD) and FC in mine although I've shot a bunch of the Starline in the 6X6.8 but not tried it in the 22X6.8. I use Type S bushing dies although I have a special run, rare, Redding 22X6.8 standard style die. While you can go from 6.8 to 22 in one pass running them down to 243 would be a wise idea.
Greg
Greg