I notice a general assumption that the military issued the ".45 Schofield" only to those carrying that revolver and that when it was phased out the ammunition became obsolete and the Army reverted back to .45 Colt. In fact, once the Schofield was adopted in 1874, even though in limited numbers, Frankford Arsenal made ONLY the shorter cartridge, and FA ammunition was the ONLY revolver ammunition issued to the Army from 1874 to the end of the Single Action era. Even after the S&W was long gone, the cartridge continued to be issued. After 1874, the Army never issued .45 Colt ammunition.
Even when the Army adopted the Colt New Service in .45 Colt as its standard handgun in 1909, they did not issue .45 Colt ammunition because they found that the small rim caused empty cases to jump the extractor, hanging the gun up. Frankford Arsenal made the Model 1909 cartridge with a larger rim and, again, that was the ONLY ammunition issued with the Model 1909 revolver. There was no contract .45 Colt ammunition. (The Model 1909 cartridge, not the .45 Schofield is the one that only three rounds can be loaded in the Model 1873 revolver, a matter of no importance to the Army since the old SAA was long obsolete in 1909.)