Jap Winchesters do not comply with the Schwing figures, but the dozens of Model 21s and Model 12s I have measured are, in fact, lightly choked as mentioned by Schwing. The listed dimensions come from Winchester internal memos and charts. I have a prewar 20 gauge Model 21 marked Modified and Full that is a bit on the loose side of the "chart" in the Modified barrel. However, the factory test patterning indicated a forty some percent test pattern for that barrel. Obviously, the factory barrel borers took a bit much out of that choke and thought no one would ever notice. I'm sure such things happen in the best of gun factories. Even today, that barrel is doing all it can do to make a good improved cylinder pattern. Oh, well.
