ORIGINAL: jeepkid
I have only saw the reloading dies listed in Graf and Sons Inc. So thats as much as I know, it just sounded like a pretty kick ass caliber. They have a bunch of cool calibers listed. I was also thinking about the 22-243, not sure though.
The middlestead is a wild round. My gunsmith builds them. He buys barrels with fast twist and was pushing some pretty heavy 22 bullets out at 4000fps. Sounds like he is only getting 800rounds per a barrel however.