[M.T. Pockets]

Horizontal distance to the target is what matters, so uphill or downhill, your bullet is going to drop according to the actual horizontal distance to your target.

I remember a well respected hunter, I believe it was Jack Atcheson, say: Sight your rifle in 2" high at 100 yards and aim right where you want it to hit out to 300 yards and forget about everything else (holdover, wind, uphill/downhill). For practical hunting, this is probably the best advice. I'm sure the guys in Long Range Shooting can give us the details on the factors that go into being a great long range shot. But for practical field hunting most guides will say that their clients miss when they think too much and don't practice enough.