Originally Posted by Adam
Ah, but! Assuming barrel is horizontal which it almost never is. If you are trying to hit a target on the same level as the sight line (and at the far zero point) the sight line is horizontal but the barrel points slightly upwards in order for the pellet to be launched at the correct angle to come back down.
And still true is that if you raise the scope height, it pushes the tangent further out. The extreme example would be a scope mounted 1000m above the gun, and the pellet fired from a gun say 10000m up, and the pellet barely travels forward anymore, but falls to the ground more... it's still possible for the LOS to just touch that curve (we're talking ideal real world obviously here where in that extreme the pellet still moves forward).
I made the example horizontal just in case someone said 'what if?'...
Which all reminds me i've got some drawings to do for CompAir for Brian's article on shooting up and downhill