For this test, I was using Hornady's 123 gr SST polymer-tipped bullet, Reloder 7 powder, and CCI #200 large rifle primers. I tested 5 loads, 25.9 gr, 26.2 gr, 26.5 gr, 26.8 gr, and 27.1 gr. That last one is .1 gr over max according to most manuals. Here are the results for each one....
25.9

26.2

26.5

26.8

27.1

Two of those groups are right on the edge of 1 MOA, so there's got to be something happening there. I'm probably going to run another test from 26.5 to 27.1 to see if anything changes. All three of those seem to have the same point of impact, so the OCW may be in that range somewhere.