Not quite. You hone out 10 points and leave the choke intact, what was improved cyl. is now modified. I believe I misconstrued your take on my 54 points of constriction. What you "always say" isn't quite to the point either. Very easy to determine absolute "choke size" (ID at muzzle exit) with something as simple as a slide caliper. Should read "you can't know relative constriction (and nominal choke) unless you know bore size). Example: bore (as in my Ideal): .721". choke exit: .667". Viola: 54 points/mils/thous constriction. The fact that I read it off a bore mic zeroed to bore diameter is simply my favored "easy read" technique. I do agree that the turned brass "ringsizer" type choke gauges are worthless.

jack