I am grouping about 8-12" high. Are you saying that if I move the front sight toward the stock, and the rear sight away from the stock, the impact point will move down? I wasn't aware of this type of adjustment (shows you I'm a newbie). Yes, I do have a ventilated rib so I could do this.

UncleNorby - I was using 1800 fps Remington Sluggers high velocity ... I don't know if I can get much faster than that! My shoulder is killing me today ... I never shot that many slugs at once.