One component of this issue worth taking into consideration is whether the impact velocity of the bullet at 800 yards is still above the 2,000 fps threshold. Because much below that, bullets can generally only make a wound channel the size of their frontal diameter. If the bullet is fairly large to begin with, then this may not be much of a problem. But if the bullet is 105 grain .243, it really needs the impact velocity to make a respectable wound channel. Sometimes I hate to see debates get fired up over this foot pounds quantification. All that really matters is the size/shape of permanent wound channel the bullet can produce once it strikes the animal.