Throughout all of my manuals there is an average of about 100-150 fps between the RUM and the 300 Win Mag. I admit that I am a fan of the 300 Win Mag and for me there is no reason for the extra powder and cost of components of the RUM. I loaded my 300 Win Mag to about 2900 fps unless I needed the extra velocity(which I never did.) I have seen the results of any good 180 grain bullet @ 2900-3000 fps on all sizes of big game. I see no need to put more stress on the bullets when they perform so well at moderate speeds. Everything I killed with my 300 Win Mag, could have and has been killed by the 30-06 at velocities quite a bit less than those produced by the 300 Win Mag. I quess some folks feel the need to eek out the max velocity from every cartridge. For those the 300 Ultr super max mags are there to please. I don't need it and the 300 Win Mag is more than need I at its humble velocity. Good Hunting.