I have never shot a slug before so I have a few questions. I recently bought a remmington 870 with a 28" ribbed barrel and a 21" slug barrel. the slug barrel is not rifled. What are the differences between a slug barrel and a standard shotgun barrel. I know it is shorter, has different sights, and no choke. but is the inside diamiter a little diferent/ is the medal different? I just bought a box of rifled slugs and plan on shooting them next weekend. What kind of accuracy can I expect? if I bought a rifles barrel and used non rifled slugs would I get better accuracy?