RE: 300.wsm vs. 300 rem ultra mag.
I've owned and shot both. The RUM is the flatter shooter, but its recoil is considerably more than the WSM. Unless you have coastal bears on your hunt card, I'd forget the RUM and get the WSM. The 300WSM is the most popular WSM cartridge out there, and ammo is rapidly becoming available in places where it wasn't just a year ago. The RUM, while maintaining a degree of popularity, is losing market share (or so a Rem rep told me about 3 months ago).