ok well if you get a slug gun and its barrle is fully rifled you can only shoot slugs and you want to shoot sabots with fully rifled barrles, now with a normal smooth bore shotgun you would normally shoot rifled slugs and buckshot, DONT SHOOT BUCK SHOT IN THE FULLY RIFLED BARRLE it will ruin the rifling, and yes the SXS and over and under shotgun are better for birds but i am sure you could shoot slugs if there choke is right.