stay with the mod choke or better yet(if there screw in chokes)go with the improved cylinder.full choke is to tight.your right about the rifled barrel,a smooth bore barrel works great for up close and personal sluging.brenneke makes a fine slug but don't limit your self with out testing other brands.every gun(shotgun or rifle)shoots differently,what works in mine may not work in yours.find the one that shoots best in your gun.my favorite is 1 1/4 oz active slugs,deadly accurate out to 100 yards.