I used slugs with the wad attached to the back of the slug. 20 bbl Remington 11-87 Police smooth bore - 3" chamber.
Sighted at 50 yds, the group could be covered with the palm of your hand.
At 100yds (with the same sight setting), the group would easily stay on a 9" paper plate. The center of the group was 9" low from point of aim,(with the 50 yd sight setting).