I was always told to only shoot sabots through a rifled barrel. That's all that I've ever put through my 20ga. w/ rifled barrel. I can't say for certain not to shoot regular slugs because I've never done it. But it is what I was always told. They told me it would ruin the rifling. Plus most regular slugs have rifling on the slug so it counter-acts the barrel's rifling. But again, I'm no expert.