I've killed a lot of big game in Colorado with my 300RUM, but every animal was less than 100 yards. A couple of elk I killed were less than 30 yards. If you look at the ballistics on the 300RUM a 180 grain is dropping a 12" at 400 yards and over 25" at 500 yards. I think to make those kind of shots would take more time practicing and more money for ammo than I can afford. I know I can be effective to 250 yards with my 375H&H, 300 yards with my .270, and 350 with my 300 RUM.