Stan, I have to agree with you because when some one tells me the choke of a gun they almost always mean constriction. I've yet to come across anyone with a pattern in their back pocket who can pull it out and provide an explanation of choke.
My understanding is choke is defined as the amount of constriction between the 'bore' measurement and the amount of constriction of the choke. That can be done with a pen and paper and some gauges. What if I were to use percentage change. .693/.729 over x/100 = 95%, a 5% constriction. So anytime I could measure the bores and chokes and get a 5% constriction I could say I had a full choke?
What shot I use or what pattern I obtain is irrelevant because that 5% constriction is really my only constant and what I am trying to determine is some reference for the amounts of constriction. When a seller tells me that the chokes are 5/8 and 3/4 I have no idea what that means.
My question is not to understand how a certain type of shell performs in a particular shotgun. I don't look at it the way Ian has described. I would turn it around and say that I have a 5% constriction, a full choke, and in this gun with this wad, shot size, pressure, velocity is how that shell performs with a 5% constriction. And is should perform somewhat similarly in any gun with a 5% constriction. I realize that may be somewhat simplistic as there are many more variables from barrel to barrel.
Perhaps I am way off the mark in my understanding. If I follow Ian's description then my first question would be what pattern describes what choke?
