Re: OCW test with PP 2000 MR .308 @ 200 yards.
Measure each hole in each of the groups horizontally and vertically using the center dot as point 0,0 with positive up or right of center; negative being down or left of center .
Average each three horizontal measurements and each three vertical measurements to get the group center. That will yield as many ordered pairs as you have 3 shot groups.
Plot each point on a clean target and connect the points in sequence. you can see how the cwnter of the group is moving around.
Small movement between centers indicates stability of powder load. That is what you want with OCW.
Group size for OCW really doesn't mean much as long as all of the shots were "good" shots.
Picking a charge weight between two or among three is fine. After this you can do seating depth checks.
It's OK if you don't do it like me!