I have a 20g Remington 870 Express and I'm trying to figure out if I need a rifled barrel to shoot slugs or can I just shoot them from the stock barrel. I've heard 2 different things and trying to get some clarification. thanks.
You get much greater accuracy out of a rifled barrel but there is no problem shooting a slug out of a factory smoothbore as long as you dont have a tight choke on the end. Most slugs can squeez down enough to do it, however a tight choke can damage the end of your barrel and effect accuracy.
Depends on what type slug you plan to use. Normal, old-fashioned "rifled slugs" - foster slugs - work fine in either smooth or rifled barrels. Sabot slugs, however, were designed to be used in rifled barrels, and don't work well in smoothbores.