In 1932, Fred Moore was the factory superintendent at Colt's and did experimental work with a new cartridge which was designed to be a better man stopper than the .38 Special. Remember, this is three years before the advent of the .357 Magnum. The Colt Official Police revolver was chambered for the .41 Colt Special and three variations of ammunition were tried using 210 grain bullets at 810, 925, and 1150 feet per second. The last loading was used in the larger framed Colt New Service. Remington supplied the ammunition and the latter was made long enough so that it would not chamber in the shorter cylindered Official Police. If you should happen to run across a .41 Magnum cartridge without a headstamp, chances are very good that you have the very rare .41 Colt Special.