My Model 12 16 ga made in 1924 has the short chamber and i just use the B&P Shorter 16 GA shells. I have the 2-3/4 inch reamer, but not worth the effort as well as it shoots with the B&P ammo
bea175 - I think we talked about this a year or two ago. Your Winny M12 16 ga looks a lot like mine.
Full choke and short barrel ?