What "category" are you talking about? When it comes to supersonic external ballistics, the only categories that matter are drag profile and velocity. We generally represent the drag profile with an appropriately modeled ballistic coefficient.
7RM - 180gr ELD-M, 0.401 G7 BC, 2950 fps (or if you prefer) 195 Elite Hybrid, 0.387 G7 BC, 2900 fps
.300RUM - 225gr ELD-M, 0.391 G7 BC, 2900 fps
I don't mean to rain on your parade, but fantasizing the RUM doesn't change physics. The .300 RUM is a great chambering for specific applications, but it's not magic.
