I am goinbg to do a 20 Ga Bore Rifle. I bought an H&R 410 single shot, sent it back and had two 20 Ga rifled slug barrels fit. They are 60 bucks a piece. You will have to cut the lug assembly and sights off but they are turned down pretty good already, save a lot of lathe time. 24" long. Will see how it works when I get back from Iraq fall of 09.