I have a couple 264s and would take any critter in the U.S. with one save Bison, brown bear or polar bear. That being said a lot of polar bears were shot in Norway with the 6.5x55 which is slower. Still, I'd trust it for anything huntable in washington at any range I can shoot at. The .264 caliber bullet is a great combination of ballistic coefficient and the often overlooked sectional density. The mass and velocity applied to a comparatively small area makes for excellent penetration with a bullet designed to hold up to the desired impact velocities. The 264 will serve you well.
