The water is even muddier than those charts illustrate. If you do a search for the nominal definitions of choke (% at 40 yds) you will see what I mean. Is IC 45%? 50%? Depends on who you read.
Then, consider that shotcups skewed just about every vintage shotgun barrel in the tighter direction. Full = just 70%? Guess again.
Then there are the skeet definitions which, originally (sorry, Briley), weren't defined as a % at 40 yds at all.
I've pretty much stopped even thinking in terms of anything but numerical points of constriction. What's in my ASE90? .019 and .019.
Sam
