I was helping a friend sight in his new kodiak and this is what happened. We started at 25 yards and the first shot hit the top of the paper. We moved the rear sight down two notches and the second shot hit right next to the first. We moved the rear sight down three notches and hit same elevation. We continued to move the rear sight all the way down with no change in elevation. We shot four times and they all hit the top of the paper. He is shooting 100 grains of pyrodex pellets and I think power belt bullets. Any explanation would be greatly appreciated. Thanks..