RE: 800 yards
800 yds for a .308 does seem a little of a stretch for deer of any kind. The cartridge will shoot that far. It is the printed maximum effective range of the .308 Sniper Rifle. Would be good at the range for Prairie dogs maybe, but just lacking the energy for deer. Would be more feasible with maybe a 300 WinMag, or a .338.
That range though seems just a little irresponsible for any bullet.