RE: rifled shotgun?
I looked and hastings sells some barreta barrels, but it didn't say anything about stoeger. You would have to check and see what barrel it takes for sure.
I did a search for stoeger replacement barrels and came up with zilch. Stoeger does make a 2000 combo gun with a slug barrel, so they are out there. I just don't know how you would get a hold of one. Contact a dealer and see if they could order you one I guess.
Paul