Hey folks. Have a question. I've got a Winchester Black Shadow Turkey, Model 1300. It has screw in chokes, but it came with just full for turkey. I've been told that the readily available Mossberg tubes are interchangeable. True, and if so, do they fit flush? The Mossberg tubes I've seen do not have a knurled area that sticks out past the barrel a little. What say you? Thanks for your responses.