Couple points here:
1. When figuring percentages, it's not wise to go by the "book" numbers for how many pellets of a given shot size and given shot charge you'll find in a load. I've counted pellets in shells marked 1 oz 6 that have ranged from under 200 up to 250. The "book" number of 225 is right in the middle, but that doesn't help you much when you're at one extreme or the other.
2. If you shoot at 40 yards, you need a bigger piece of paper than used in the first pattern photos above. Otherwise, a small aiming error will move part of your 30" circle off the sheet.
3. If you shoot at closer range (like 30 yards or less, which I usually do), I have not observed that there's extreme variation from shot to shot. That may occur as a result of aiming error and a pattern sheet that's too small at 40 yards, however.
4. I pretty much gave up on Dr. Jones when I read about how many broken clay targets he attributes to a single pellet strike. That contention alone told me that he needs to get away from his computer and spend some time picking up unbroken clay targets with a hole or holes. I don't know how many clay targets break as a result of a single pellet strike, but I do know I've found plenty that don't, some that don't break from 2 pellet strikes, and the occasional target that doesn't break from 3 hits.
