I just finished an exhaustive test of all the most common lead and tungsten-based 20 gauge shotshells. It took several months, due to all the odd weather that we've had but I think that there was an actual benefit to that. I was able to fire an equal number of shells at each session with various weather conditions, just like we encounter in turkey hunting.
This is a study strictly for hunting purposes so I used an area that's comparable to a 20" circle, an area that I consider to be a good test for a hunting load. I did look at patterns and considered core density and overall density but concentrated mainly on the number of "hits" in the area. All shots were at 40 yards.
I tested a variety of choke exit diameters initially but after examining the results, reduced the test examples to 3 sizes. I did this for 2 reasons. The first was the effectiveness or lack thereof of the choke and the second was the number of patterns needed to be shot for the study to be meaningful and the number of targets that would add to the study, without adding much in the way of useful information.
I also limited my study to common commercial loads in #5 or #6 shot. I'd previously run tests at the request of Tungsten Super Shot with their #7 and #8 shot loads. I did not test any Nitro shells.
I'm putting the finishing touches on the article, reviewing all my tabulations to make sure I have no errors, and will publish it soon. I hope you will find it at least interesting and hopefully helpful.
"If he's out of range, it just means that he has another day and so do you."