.....26" modified choke barrel that mikes out at .009" of constriction. Not sure if the choke was opened up or came from the factory that open.
Quite possibly original. WW's pre-64 mod will usually have less constriction vs Briley's 0.015" spec. Helps to know bore diameter as well as terminal constriction diameter - not just net constriction - and whether there's a long parallel extending to muzzle.