Vapodog,
You have the right idea. I do use MAD to help determine the best powder for a load / weapon by finding the powder that produces the lowest MAD with the smallest groups. I will work up loads with several powders and the winner is the one that does both good groups AND low MAD. That way the barrel harmonics are in conjunction with the lowest deviations in velocity and I get the best chance of consistancy in my loads.

PaulS

Think safety, act safely, live long enough to enjoy it