Don Zutz published an article "Tricks Powders Play" in the 90s reporting improved patterns with Green Dot and Solo 1250. I could not find the original on the internet.

I could not find a pattern study comparing slow and fast powders by Neil Winston. I believe it is an accurate reflection of his opinions that pellet hardness/resistance to deformation is the primary determinant of pattern efficiency, with some contribution from wad design.

David J. Compton, “An Experimental and Theoretical Investigation of Shot Cloud Ballistics”, 1996
http://discovery.ucl.ac.uk/1382490/1/396689.pdf
Discussed here
https://www.trapshooters.com/threads/abandon-all-hope-of-understanding-shotshell-ballistics.601793/

Blame the mythology on Wallace Coxe, “Smokeless Shotgun Powders: Their Development, Composition and Ballistic Characteristics”, 1927

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