There are literally 2 shots making this bigger than 2”
The more shots in a group, the greater the statical average will be, simply because the more shots the greater the odds of more "fliers" opening up the group size.
Does this matter?
There is a lot of discussion about how many shots should be considered a group, or the "right" group size. Numbers say the more data points the more accurate it is, and this matters to many people.
Doesn't matter so much, to me. I've always figured the number of shots in a group should be the number of rounds the gun holds, or less if the gun holds a lot. 5rnds is some people's standard, others 10, others more. All depends on what matters to you.
For revolvers, I go with six rounds (all my revolvers hold 6) and that's a group. TO me an 18shot group is not a group, its 3 groups on top of each other, and since there is always some amount of error, three "2 inch" groups, shot on top of each other COULD give you a total group size of 2, 3, 4, or even 6 inches. Does that tell you how accurate your load is? I don't see that. Tells you something about your shooting but not so much about your ammo's capability.
Another point to consider, about group size, bigger bullets can all be overlapping holes and still measure more than smaller ones.
5 .45caliber slugs can make one ragged rip and still be a 2.5" group.
Does that matter to you?
This is a 100 yd MAX gun. Is Sd really important?
Drop at 100 yds = -5
-3 Sd = -7; +3 Sd = -3
So 100 yd dispersion is likely 15” …11” from the group projection +4” of Sd dispersion. Probably just need to limit myself to 75 yards until I or the load shoot better. I’m ok with that. I’ll bet I can put a number of these on 12” 100 yd steel!
I see Sd will effect group size, possibly beyond minute of deer, but I also, see that 100 yards is way beyond my 45 Colt
Different shooters, guns and loads will have difference capabilities. Speaking strictly about hitting a steel target (and not a game animal) in my younger days before I got old, weak, and nearly blind, I could regularly ring the 200yd gong on the range shooting my 7.5" .45 Colt Blackhawk, off hand, one handed, and 5 out of six on a bad day. OF course I had a bit of practice, having spent nearly 30 years doing just that for recreation, shooting one bullet and one load, and learning exactly how to hold to do it. And I could do it with other guns as well, after a few sighter shots.
I never really bothered with group sizes and completely ignored SD and ES though I did chrono the load one time and it was avg 1070fps. Since I could hit what I wanted to hit at the range I wanted to hit it, all the rest didn't matter much or any, to me.
Numbers don't lie, they say, but to me they aren't the be all end all and its results down range that matter most to me. A handful of fps variation hardly seems to matter if you hit your intended target where you mean to hit it.
I'm rather old fashioned I guess...