A complicated subject: First we have to classify whether we are talking breaking clays or killing birds.
A choke that will break a clay may only wound a bird.
I shoot several thousand rounds a year at sporting Clays and a LOT less than that at birds.
I use a .012-.015 choke for about all Sporting up to 45 yds and it breaks everything that I think should have broken. I shot the same choke last weekend at a Station which had an edge on 50 yd clay and I am confident my choke was too open. Of course a bird
would have been wounded if hit at that distance with that choke.
when we are shooting birds at distance over about 25 yds , I do not agree with McIntosh either. I have wounded Quail and Dove with a choke too open when the distance is too far for the constriction. I use IC for Quail and Mod usually for Dove and Duck.