I don't mind friendly debate. I'll send you a cheekpiece anytime you want.
I was taught long ago it didn't matter if it was up or downhill and have applyed that in the field ever since without giving much thought to it other than the base theory. I have had great success with disregarding up or down. That being said I have not had opportunity to shoot up/downhill shots of huge distance and angle. 2000 yard shots with any angle at all (say over 15 degrees) just don't happen in this part of the world. What you say about the up/downhill gravity effect makes since to me I just have never seen it in the field ( that doesn't mean it isn't happening). I am sure that gravational deceleration occurs and will effect a given shot to a given extent. I beleive that few would ever have the occasion to shoot the distance and angle for it to be an issue. If the effect occurs at 3000 yards with an angle of 15 degrees or more I am not to worried about that. I will continue to teach that it doesn't matter, simply because it occurs at distances and angles rarely encountered by anyone. So I guess in my mind it is one of those issues where it does exist but is such a rare field occurance that it would only serve to confuse the subject and most people. It is an interesting issue and I am glad it was brought up. I like to know what is technically correct even if it doesn't effect my shooting.
As a side note to all who posted, this is likely the only civilized site left on the web lets keep it that way.