I do not own a 7 RUM but I do own a 300 Rum and from my experience with the RUMs it would seem to be a better purchase to get a 300 if you can. The 300 seems to be more of a mainstay with the gun community and you will be probably be able to get ammo (if you dont reload) for the 300 alot longer than the 7 rum. Just my .02 worth.