In the Sept. 1928 issue of "Hunting and Fishing" there is an article by W.H. Foster "An Analysis of Shotgun Performance in Skeet" and a Remington "New Remington Skeet Loads" ad.
Unfortunately, there is no description of what makes the "Scatterloads" scatter, and in 12g both loads are #8s, 3 Dr. Eq. 1 1/8 oz.

Remington-U.M.C. "Scatter Load" boxes

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[Linked Image from photos.smugmug.com]