Play with a ballistics calculator and will it show the effects of sight height. They have an input for sight height on most of them. It has to do with the line of sight vrs the path of the bullet. That is why it seems like a bullet rises and then drops again when you shoot it. That is not what really happens at all. The bullet is constantly dropping after it is fired. But because the sight is higher than the bore of the barrel your barrel is actually pointed upwards to a certain degree when you shoot. The point where the bullet is higher in the trajectory path is where your line of sight intersects the path of the bullet.

The higher your sight height, the more flat the rifle seem to shoot at longer distances. But like said above you will have to raise your cheak off the stock to look thru the scope. Not that big of a deal if you are shooting where the parallex is set for (100 yards normally), but if you are shooting at like 150 or 50 yards it may cause you to be a little off. Unless you have a scope with an adjustable objective, if it set properly for the yardage you are shooting you should be able to move your eye around quite a bit with it effecting the impact point.

Paul