That is very interesting. While some would look at the total velocity what impresses me is the difference between high and low.
5/32 shows only 11 feet difference while the 1/8 shows 27 feet per second difference
,the 19 feet per second faster by the 1/8 is almost immaterial by comparison to the consistency of the 5/32.
I have a question: with the velocity starting high and tapering down, were both groups started on a clean barrel?