The main thing is to remember that pattern is independent of barrel length. Choke is part of it, but the difference among various loads is apparently the biggest factor. E.g, my ancient Model 12 is near-perfection with Winchester high-brass heavy loads of 7-1/2, but horrible with field loads or dove/quail loads.
What is as important as the percentage of hits within a circle is that there are no blank areas, no "holidays" in the pattern...
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