I am a fan of the 7RM having worn out three of them so far, but if building I would look at the 7mm Mashburn or the 7mmx300 win. with the Mashburn being a better design due to a longer neck.
The 280AI is another favorite and the Rem. 7 SAUM is a better designed short version of that capacity case. Not sure I buy the inherent accuracy claims but it is similar to a PPC on steroids and no doubt as to it being accurate. Possibly more accurate than the 7RM with fewer magnum velocity swings. I would put it in a medium action or even a long one and twist it for up to 195 grain bullets although I would probably use 160-180 most of the time.
