Why? For hunting trophy Coues deer. Anyone who has hunted this deer knows you don't stumble on a 100+ BC deer. You usually glass them from half a mile with something like Zeiss 15x60 binoculars on a tripod, and try to stalk within range for a shot. These educated trophy deer do not bed down in a place where they can be easily ambushed; sometimes but rarely. Since the best time to see a trophy Buck is durining the late winter rut hunt, these deer are on the move trailing does. 500 or 600 yards is not uncommon to put your rifle over your pack or on a tripod and wait for that moving deer to stop for a shot. When he decides to bed down, it will be on a high point where he can't be ambushed and he can see the does if they get up to move. Find a trophy Coues deer hunter who has killed few and find out what gun he used. Things like Weatherby 300 or Remington 300 Ultra Mag will not be uncommon for these little deer that don't weigh over a 100 lbs. Why? Because they want a flat shooting fast bullet that will consistently hit the target at ranges over 500 yards.