By the end of the 1800s, during the Spanish-American War, the US military noted that their service revolvers (the Colt New Army Model 1892 chambered in .38 Long Colt) did not have enough power to stop attackers in their tracks.
The US Army considered two possible cartridges, the .41 and .45 calibers, and after extensive testing, they opted for the new .45 ACP round. At the invitation of the government, Mr. John Moses Browning, a genius known for creating and developing some of the best firearms ever made, sailed from Europe to help with the situation.
ARMY BARRACKS 