A rifled barrel is meant to shoot the sabot slugs. A sabot is a plastic or polymer holder that hold the bullet and engages the rifling as it travels down the barrel. A box of 5 will run you between $10-$15.00. What kind of sights are you using? If you mount a scope you can have it boresighted and you won't have to shoot that much to be ready for the field. I'm not sure what you meant by "smooth slugs". I've never heard them called that. A rifled barrel with sabot slugs are deadly on deer and hogs and a lot more accurate than rifled slugs through a smootbore barrel. Definately worth the investment.