Sabotloader - seeing as how you're all tied up in huddles, and I was curious, I did some homework for you. The sectional densities are identical at .175. Speer lists the BC at .165 and Hornady at .146.

My theory is the shooter believed in one bullet and not the other.

Cdaddy has agreed to administer a blind test with you as the shooter, varying bullets loaded, and on occasion leaving out the primer to check for steadiness. 5 of each bullet will be shot. If one of the bullets groups farther from POI than the other, you will wash his truck. If all bullets travel through a single hole, he will wash yours.

Seriously, what's your theory on this odd grouping?