"Correct, Keith was not referring to the .45 Schofield as someone speculated above. They were only loaded by Remington UMC (that's a clue as to how long ago) and had the standard rim size of the longer .45 Colt, not the wide rim of the Schofield which is the "dead giveaway"."

The .45 Colt and the shorter .45 Schofield cartridges have, within manufacturing tolerances, the same rim size. I have measured quite a few of them, and found only a few thousandths of an inch differences. I'd suspect that the great majority of Schofield cartridges were loaded at Frankford Arsenal for Army use. Most every civilian shooter would have used .45 Colt cartridges, unless he had a Schofield revolver. Indeed, the .45 Smith & Wesson (aka .45 Schofield) cartridge was loaded by UMC, and later Remington. It was last listed in the 1937 Remington ammunition catalog.

The .45 round with the oversized rim diameter was the Army's short-lived ".45 Caliber Ball Cartridge, Model of 1909," made for the Colt New Service Model 1909 revolver. It was loaded only at Frankford Arsenal. There's always been debate as to why it had a larger rim, but the official reason given was for more positive extraction from the Colt Model 1909 revolver. However, the .45 Colt and .45 Schofield cartridges will also work OK in the M1909 revolver.