I agree with the taper toward the muzzle as you said but not with the expanding forward from a point 1/4 inch or so back from the muzzle. Where are you getting those specs? I have measured chokes in 6 Model 21's and the only one that expands in the last section toward the muzzle is an original WS1 skeet choke. All the rest were conical-parallel. Original modified chokes will measure 20 points or tighter. I have never seen one that is more open than 20 points. Improved modified will run about 25 to 30 points and full choke 30 points or more. Sorry but if yours are more open than those specs I think they are suspect.
