My friend has a 6mm X 30-30 AI built by Mike Bellm in Oregon. It is one of those barrel and cartridge combo's that makes me drool with envy. Although quite happy with my .257 JDJ, I still always secretly wanted to swindle him out of it.....
I had Mike build me a .30 cal based on the .444 case, yet it uses standard .308 Win dies to bump the shoulder back and neck size. Coincidentally it is called the .308 Bellm. What a shooter!!
This guy rocks. I think he has forgotten more about Contenders than most will ever know.
(this site has a ton of helpful articles on it, even though it says "store")