no expierence with buckshot,but slugs are deadly .yes they make slugs for smoothbores check out some brennekes,federal truball,remington.they all make slugs for smoothbores.make sure you do not shoot a slug meant for a rifled barrel out of your smoothbore.
Use slugs. For a smoothbore barrel you WANT a rifled slug. If you had a rifled barrel then you would want a sabot slugs...but if you had a rifled barrel you couldn't shoot buckshot. What are the specs on your current barrel?
Not saying your a bad shot or anything...but you may want to look into a slug barrel for your shotgun if you can..you didn't state what kind of gun it is. Its hard to shoot accurately with just a bead sight...I don't think I would risk taking that hunting personally.