To me, that looks like an unusually large POI distribution for 100 yards. I don't have experience with this exact bullet and cartridge, but I expect to see 1-1.5MOA groups when shooting a ladder test at 100 yards in all of my rifles. I don't normally do 1 grain increments though so maybe that is the difference. How many rounds are on this barrel at the beginning of the test?
Edit: I did go look back through some old 10 shot ladder targets and I do have some that seem to string out like yours did, just not quite as extreme. I haven't done 10 shot ladders for quite a while so I had to refresh my memory. I have seen quite a few ladders that produce sub MOA groups at 100 yards though.