It just hit me. Nobody is celebrating the 100 year anniversary of the 45 ACP cartridge. Every article and discussion I've seen is only about the anniversary of the 1911 pistol. The 45 ACP however has gone on to other pistol designs too and still serves today with some Special Forces Units. Here's the timeline... 1904: Thompson-LaGarde Tests—caliber of new handgun should be at least .45 1906–1907: Handgun trials—Colt enters with .45 ACP design 1910: Final tests—Colt pistol (designed by John Browning) out-performs Savage March 29, 1911: The Colt pistol is officially adopted as the Model 1911—and with it, the .45 ACP cartridge. .45 ACP - Wikipedia, the free encyclopedia Happy Anniversary!