John, you may not need a new barrel. My Dad's 1100 with a vent rib works very well with slugs. I got a set of sights that attach to the vent rib and killed 4 or 5 deer with it. Accuracy was 2 - 3 inches at 50 yards. Choke is improved cylinder.
What choke system do you have? Vent rib?
Giz