Bound by the Rollin White patent () and not wanting to pay a royalty fee to Smith & Wesson, Colt could not begin development of bored-through revolver cylinders for metallic cartridge use until April 4, 1869. For the design, Colt turned to two of its best engineers: William Mason and Charles Brinckerhoff Richards who had developed a number of revolvers and black powder conversions for the company. Their effort was designed for the United States government service revolver trials of 1872 by Colt's Patent Firearms Manufacturing Company and adopted as the standard military service revolver. Production began in 1873 with the Single Action Army model 1873, also referred to as the "New Model Army Metallic Cartridge Revolving Pistol".