IMO every reliable rifle can shoot and kill at that distance. It's not the gun or caliber as much as it is the shooter and scope.

You've got to know your ballistics out to that distance. Scopes used for that either have some kind of bullet drop reticle or an adjustable elevation turret. They "dial in" the distance on the turret, and let 'er go. I've seen a DVD by this guy in Wyoming where they are dropping elk in their tracks at 700 yards and beyond. Unbelievable. The guns used are customized and have that type of scope on them. And, most important, practice / praCTICE / PRACTICE! I think they said the caliber was closest to a 7mm Mag.