WKevinD had your aim been 1 1/2" higher, it would have centred the head. That load would most likely work to 40yards, given the extremely tight concentration
in the centre of the pattern. I suspect you aimed down, along the barrel, instead of having your eye just above the breech. That is a tendency when patterning
but usually doesn't happen when shooting game - unless it is purposefully done.
You have developed a very good patterning load.