I don't have Brister's book in front of me but recall that the 20 ga skeet scores he looked at were closer to the 28 ga scores than the 12 ga. scores, suggesting that, although a 20 ga. falls exactly between a 12 and a 28 gauge-wise, it "underperformed" a bit relative to the other two gauges. Maybe he was not using a perfect metric, but those scores would indicate there is not a linear relationship between gauge and effectiveness at the skeet range.

Of course we don't know what loads were being shot for all of those scores . . . .

Such a long, long time to be gone, and a short time to be there.