my question is that of an 18 and a half inch cylinder bore barrel rifled slugs are okay to shoot out of it not the Sabot slugs am I right? I just wanted to make sure before I bought some.
As posted, either would be safe to shoot, but (generally) smoothbores do better with Foster-type (or Breneke) slugs; and rifled slug guns do better with sabot slugs.
Yes they're perfectly safe to shoot out of a cylinder bore. However I do recommend trying several different brands of ammo and seeing which slugs fit your barrel the best. With Remington slugs I can shoot a four inch group with open sights of my 18.5 inch barrel Mossberg. With federal slugs the group was three feet! I actually missed a 55 gallon drum several times. This was not Federals fault the Remington slugs just fit my bore better.
Boomer