This will be my first time hunting Bighorn Sheep, will be in MT. I have narrowed my choices to two of my long range rifles 264 WM or 30-378 WBY, both have Nightforce 5.5 X 22 NXS scopes, we will be in Grizzly country and my partner will be carrying a 7mm MAG. I can shoot both guns equally, comfortable kill range for me will be out to 500 yards maybe push a little more, but I hope not to have to push any further. Please give me your reasons why one over the other. I thank all of you for your information.