Moses;
My very first experience with loading shotshells was back in the late 1950s. I loaded brass 20 ga shells I acquired from Alcan, Fiocchi brand. These were primed with Berdan primers which made for rather slow reloading but it worked for the amount of shooting I was doing at the time. I loaded with smokeless powder exclusively. Only the quick burning powders could be properly ignited such as Red Dot, Dupont bulk & an imported powder know as Nike.
Black powder was very easy to ignite & I think many of the primers available in the early days for the brass shells simply would not satisfactorily ignite the smokeless powders. A bit later Alcan brought out a line of brass shells using the old Remington 57 shotshell primers which could be satisfactorily used with any of the smokeless powders. As I recall these were only available in 12ga. They were made to fit a 2 3/4" chamber but would effectively hold the 3" magnum load.
I hope this answers your question just a bit, but I really feel it was the matter of ignition.
