Not knowing which ammo you were shooting for a given group in a series of say ten groups, with perturbations of one kernel of powder vs. dead nuts?
How about you prove it doesn't matter......
Have you got the ability and equipment?62 pounds with an 8" forend and 3" butt makes for a pretty good test vehicle....
I thought you might go that way with the discussion, but it doesn't really address the question. Make no mistake, I'm not of the belief that since I can't do it then you can't either. I know I don't have the skill and equipment to resolve such a fine detail. To prove it does/doesn't matter requires the equipment and skill
you possess. My sticking point is you'd need to run a several blind tests.