Rifled barrel, + Magnum Slug= Win. Moving targets are hard, but not idle. As for buckshot, run a full or extra full choke and 3" or 3 1/2" load- 15-18 pellets 00. My Benelli Nova 12 has spread that can hit vitals at 100 yrds with that. Admittedly, 20ga is better for long-range slugs, but 12 isn't bad. You just need proper rifling and proper sights: if you're smooth-boring and using double-bead, you're doing it wrong. Also, Sabot Slugs > Foster Slugs.