Horse-stopper, yes. If some old, old, writer's are to be believed, the .45 Colt cartridge was designed as a "horse-stopping" round. Primarily a Cavalry arm, the pistol had to be effective against other cavalry horses as the horses in a Cavalry against Cavalry engagement were more often the target than their riders. The first Colt 1873's were tested against cow's and condemned horse's and data was kept on wound location, how functional the animal was after being hit and time it took to die. Also, the Colt 1911 .45 ACP cartridge was the winner in the .38 Colt, 9MM parabellum, .45 Colt trials in the early 1900's. They used pigs and "stag's" (steer's) for that one. Pretty disgusting, but how about the "Goat Test's" in Strasburg? That wasn't too many years ago.