At 40 yards Gapper make a three foot circle on some butcher paper. aim at the bottom of the circle (6 o'clock position) and touch it off. Bottom of the pattern should start at 6 o'clock. Raise the comb to shoot higher and drop the comb to shoot lower. Opposite way for an adjustable rib. lower the rib to raise poi, raise the rib to drop poi.
Brady Gies