Assuming the gun has a rifled barrel, i have a 20 gauge Mossberg slug gun with the rifled barrel and the Remington accutips or Remington copper solids were great average group size. Every gun is different but those are 2 good rounds. Hornady makes some nice slugs but im just not a hornady fan except for certain rifle ammo. But try those or try the Winchesters. I cant remember the name right now, if i find an empty box or something ill let you know. It was a black box with gold writing i think. They shot great out the 12guage and just about the same out of the 20.