There are some things I don't understand about the 1909. They definitely needed some new pistols. All they had were underpowered .38s and obsolete single action .45s, all well worn by that time. They could not know that Mr Browning and Colt would come up with a satisfactory automatic in only two more years.

What I don't get is the large rim .45 Colt a la Frankford Arsenal.
There was an official .45 revolver cartridge defined in 1906 for the upcoming trials. It was just like the .45 auto cartridge except it had a rim. Not the thick rim of the 1920 .45 Auto Rim, but a normal .060" rim on a case the same length as .45 auto. Which itself looked suspiciously like what Colt was already selling in the 1905 guns. So why didn't they buy revolvers in .45 1906 instead of modifying the .45 1873 for simultaneous extraction and smokeless powder?