The box in front of me says 20 caliber.45 ball cartridges, Model of 1909; for Colt's double action revolver, Model of 1909; smokeless powder; muzzle velocity 725 / 25 feet per second; manufactured at Frankford Arsenal; class 47, division 1, drawing 3; R.S.Q.Lot NO. 4, of 1911. Iv'e had this box for years and never knew anything about it, another reason this Forum is so much fun. Another notice on the box says to de-prime as soon as possible and throw them in water, clean with a brush, and dry for storage.