Developed to meet requirements specified by the U. S. Cavalry, the 45 Colt was adopted in 1873 along with the Colt Single-Action-Army revolver. The original load combined a swaged-lead, 255- to 260-grain hollow-base, round-nose bullet with 40-grains of blackpowder to generate 930 fps from the Army revolvers, as verified by actual testing done by the U. S. Military. I have reproduced the original load using semi-balloon-head cases, DuPont FFg, the CCI-300 primer, and the 255-grain Winchester factory-load-bullet that duplicates the original bullet. Fired in a first-generation Colt revolver with a 4⅝-inch barrel, velocity was 930 fps! The naysayers who made huge noise back in the 1970s about how the original ballistics claimed by Colt were exaggerated, were merely demonstrating wanton ignorance rather than demonstrated fact. The 45 Colt was, indeed, the most powerful revolver cartridge until the advent of the 357 Magnum 62 years after adoption of the Cavalry 45 Colt load. The reasoning behind the Cavalry’s insistence on such a high degree of performance was simple. Between the end of the Civil War and 1886, the number of riders in the U. S. who were thrown from the saddle and got their boot caught in the stirrup and were subsequently drug to death rivaled the number who died from all other causes; for the cattle drovers of that era, who rode rough stock and had a rodeo almost every time they mounted a new horse death by dragging equaled deaths from all other causes! (The widespread adoption of high-heeled boots in 1886 dramatically reduced that risk.) Meanwhile, the Cavalry wanted a handgun that might, just might, be available to the trooper to use in a last-ditch effort to save his life by shooting the horse. To help, the cartridge had to deliver enough energy and penetration to kill a horse fast, rather than just enough to be likely to merely irritate it into running even faster and for long enough to assure the former rider’s death! In the same vein, if it would kill the horse that was dragging you to death, it could be used to stop horses an enemy might be using in an attack, which was a tactic that went back all the way to the middle-ages when English longbowmen practiced to kill the horse and leave the rider afoot, which is no small matter when the rider was wearing so much necessarily heavy armor that he was almost useless in battle on foot. The 45 Colt load was certainly capable of doing what the Cavalry wanted it to do. Fired from horseback by an obviously talented marksman, the first two 45 Colt rounds fired in anger, using an open-top Model of ’72 Colt, accounted for two kills on Grizzly Bear. As with any revolver round, best practice is to apply a roll-crimp after seating the bullet. This helps to lock the bullet in place against chambering forces that might otherwise drive it into the case. I cannot too-strongly recommend getting a second seating-and-crimping die so you can have one adjusted to only seat the bullet and the second adjusted to only crimp the case mouth. Generally, attempting to do both operations in one step is a recipe for damaged and destroyed cases. Contrary to what many believe, the moniker 45 Long Colt is acceptable as a shorter-cased version named the 45 Short Colt was marketed at one time. Mike Venturino has a box of 45 Short Colt ammo in amazingly good condition.