Single Action revolvers (SAA stands for Single Action Army) tend to be made in .45 LONG COLT. The original version being the .45 COLT (the U.S. Army adopted a 230 gr lead slug at 850 fps) and bit later the civilian version, slightly longer, called the .45 LONG COLT which threw a 255 grain lead slug at 900+.
The Army load had a shorter case what would work though the top break Schofield top break revolver.
So in a way, there was a .45 Colt.
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