A year or so ago, I bought the scoped rifled barrel for my Rem 870 (that Bbj270 posted) from Cabela's. It's full rifled, has a double row of small ports on the upper front of each side of the barrel to reduce muzzle jump, and has a cantilever scope mount with a 3-9x Simmons scope. It looks like it should work ok.
I haven't shot it yet as most of my hunting is with CF rifles, but we do have a few special weapons restricted areas near heavily populated areas, and I occasionally hunt other states with shotgun/ML hunting areas.
I'm also looking for advise on what slugs to shoot in it.