This Winchester manufactured 30" vent rib barrel with a fixed Full choke and a bright, excellent bore is for the Super X Model 1 semi-auto shotgun in 12 gauge with a 2 3/4" chamber and features a mid length bead and the ejector.  The overall condition is very good to near excellent with light wear and a few scattered specks of surface rust.  (file photo)

Note: Winchester Super X Model 1 shotguns with the following serial numbers have been observed with this part: M54210