Lloyd,
Pattern work is interesting and can produce as many points to debate, yea even argue as the curious minds that study them. Branch all that into patterns from different gauges and it could produce all sorts of claims, factual and fictitious.
I read your question or maybe more correctly read into your question , a sought for answer of how one stacked up to the other.
In any case I too have heard it said forever that the short 12 gauge shell produces the most square pattern.
In the Uplands, I really don't think claims of patterns matters much. It has been my experience that modern shells all pattern well enough to kill grave yard dead when shot at the front half of a bird.
A good dog that can trail and retrieve, makes less good shooting look good.
