well the answer for the mononblock question was more than helpfull i was just curious about it so i figured i'd ask why not learn when you can. I don't know why i didn't think about pressure correlation not being a reflection of cartrige size i spend probably more time than i should looking at ballistics. so if i wanted to build a big bore double say in .470 NE where would i get the dementions for a atcion that could handle it.