I bought one new back in 1975, mine has a 22 or 21 inch barrel, rifle sights and is improved cylinder...I didn't know they made a slug barrel longer than 22 inches and in full choke...Back then, most were more open cylinders than that...
At any rate, mine grouped terrible with both Federal and Winchester foster type slugs but does very well with the Remington Sluggers...Inside 2 inches at 50 yards with open sights...