yeah you can definitely use buckshot for that barrel, just not a rifled barrel. sabots should only be fired out of a gun with a rifled choke tube or a rifled barrel because of the bullet's density. if you get a rifled barrel and shoot sabots out of it, you should have very tight groups. for buckshot use watever u want. it varies at different ranges. if you do shoot slugs out of your smoothbore shoot them out of skeet or improved cylinder chokes and use lead only slugs. i would reccommend rifled lead slugs.