I'm with you on the .308. Shooting 168 gr Black Hills (REAL consistent cartridge) through a Shillen barrel with a Jewell trigger andLeupold mildot glass, the Remington 700 (short action) I mess withcan hit a 12" x 21" steel plate at 924 yards in a 9 mph (+) wind.
It's more or less set up for two-legged predators, but you should be able to make ethical kills on 'yotes out to 650 yards with it, right?
Because of the ballistics of the round, I'd be hesitant to try to make a clean kill on a Whitetail or Mulie with it past 450 yds, myself. They're justtoo dang tough.