Let me refer you to the cowboy45special.com website. It gives a pretty detailed rationale behind the cartridge.
The nutshell version is this: I was shooting frontier cartridge at the time, running .45 Colt, 250s, with a full case of 777 FFG, which was not only expensive, but extreme overkill. I says to myself, "Self", if I had a case with about half the capacity under the bullet, it'd save powder, still make plenty enough smoke, and cut recoil (which is time in any game with a timer)
Of course these projects sometimes lead ya where ya don't expect to go.
Like figuring out that not only with BP, but with smokeless as well, the big old colt case wasn't that hot for reduced loads, and a case about the same length as .45 ACP would be a lot better.
Which led to "how low can we go?" questions, and that led to a fancy 130 gr HB bullet that allows the .45 Special to run dead rock minimum SASS-legal loads heads on even with the light .38s, and they still group well...
Somewhere along the way the .45 Spl le us to get involved in making em run in rifles, both Marlins specially prepared, and in toggle links with a carrier I developed (runs .44 russian too, for the .44 folks)
I may be crazy, but I'm in good company. We've sold half a million of em.