Note: Composed before last post.
Below are plots of the vertical and the horizontal. This doesn't have the classical Audette form, but the vertical trend is to be most stable at shots 8, 9, and 10. For the Horizontal it is at shots 8 and 9. Shot 10 shifts left (minus direction) significantly. About what you'd expect from a 3:00 to 9:00 gust of wind (same as a 9:00 to 3:00 momentary lull) of around 7 mph. If you didn't have that it may still be a shooter error. Hard to tell.
The horizontal follows a definite trend, like heat walking, but that could also be gradual wind pick up. Since I wasn't there, I don't know. It should be a total of about 10 mph change at 90 degrees to the gun. More if the wind is off 90 degrees.
If it's not wind, cooling the barrel between shots should help. Doing a complete barrel carbon removal (Boretech C4 or Gunzilla with overnight soaks or Slip 2000 Carbon Killer for faster action) then breaking the barrel back in with thorough copper and carbon removal between each shot (Boretech Eliminator will do both for fresh single-shot fouling) then degreasing all hydrocarbon traces (Bore Scrubber or Windex) then firing one shot, then recleaning and degreasing between each of 9 more shots is claimed by some to settle the gun in a cold bore position. I don't have proof of this, but 10 shots can't hurt much of anything but your time budget and you get to group those ten to see where your clean, cold barrel zero is as compared to its POI fouled or warm.
Bottom line is to start shooting groups with 8, 9, and 10 round robin style on three targets to see what happens.
