In 1873, Colt introduced the .45 Colt cartridge for their Peacemaker revolver. It was adopted (along with the Peacemaker) by the U. S. Army as its official handgun / caliber until 1892, when it was replaced by the .38 Long Colt.
In 1875, Smith & Wesson introduced a .45 for their Schofield revolver. That combination also was used by the U. S. Army. It is properly called the “.45 Smith & Wesson”, popularly called the “.45 Schofield”.
The Peacemaker would chamber and shoot the S&W cartridge but the Schofield would not accept the Colt cartridge. The S&W case is 1.10” long while the Colt is 1.23”. There were more Peacemakers issued than Schofields, and the issue cartridge came to be known as “Colt”. To differentiate between them, some quartermasters would ask for the Long or the Short Colt, rather than the Colt or the Smith & Wesson. Kind of rough getting into a battle with ammunition that wouldn’t chamber.
A noted writer, who I have great respect for but don’t always agree with, Paco Kelly, claims that he has seen an old cartridge box labeled “.45 Short Colt”. If so, I would guess that the box was a forgery of some sort. Collectors will pay a good deal for rarities of that type, if genuine or REAL good forgeries.
There was never a cartridge designated properly as “.45 Long Colt”, and, to the best of my knowledge, there was never a “.45 Short Colt”, Paco notwithstanding.
Adding to the confusion is the fact that Colt DID come out with a .32 Long Colt and .32 Short Colt (1875), a .38 Long Colt and .38 Short Colt (also 1875), and a .41 Long Colt and .41 Short Colt (1877).
DC