Hi, Johhny and Fuff,
Sorry for my poor wording on the cartridge lengths. The .45 1909 cartridge is the same length as the .45 Colt; the only dimensional difference is the rim diameter. The cartridge I call the .45 Government (for lack of a better name) was a compromise round, short enough to fit the S&W Schofield, yet having the same rim diameter as the .45 Colt, so it fitted both the Schofield and the SAA.
When the M1909 was adopted, the Army's intent was to be able to use that .45 Government in it. But in a revolver having that type of extractor, a shorter cartridge has less support as it comes out of the chamber, and a greater tendency to jump the extractor. (Think .22 Short in a K-22 vice .22 LR.) Both the .45 Government and .45 Colt gave problems, though not as many for the latter, due to the longer case.
So the Army decided to make its own cartridges with a larger rim than that of the .45 Colt and .45 Gov't. The result was the .45 Revolver Cartridge, Model of 1909, and that was the cartridge always issued with the Model 1909 revolver. It was never made commercially, and Colt never acknowledged it in any advertising for the New Service.
In the picture, the top rounds are a .45 Colt on the left and a .45 M1909 on the right. The bottom rounds are a .45 Government (Benet primed) on the left and a .45 M1909 on the right. I think the larger rim of the M1909 can be seen fairly easily, and its length compared with the .45 Government. FWIW, the M1909 cartridges are headstamped FA 11 11 and FA 12 13.
Jim