Years back in a shotgun sporting magazine I read an article about pattern testing the 3 inch 20 gauge against the 2 3/4 inch 16 gauge. The 16 gauge was throwing better patterns at 40 yards than the 20 gauge was throwing at 30 yards.

Granted the testing has limited application as he only compared a few shotguns with their individual barrels and chokes and forcing cones, but still very informative.