a notch in the hammer, only usable when the revolver was fully cocked. The Colt .44-caliber "Army" Model was the most widely used revolver of the Civil War. It had a six-shot, rotating cylinder, and fired a round spherical lead ball, or a conical-tipped bullet, typically propelled by a 30-grain charge of black powder, which was ignited by a small copper percussion cap that contained a volatile charge of fulminate of mercury (a substance that explodes upon being subjected to a sharp impact). The percussion cap, when struck by the hammer, ignited the powder charge. When fired, the balls had a muzzle velocity of about 900 feet per second (274 meters/second), although this depended on how much powder it was loaded with. Metallic cartridge era The Smith & Wesson Model 1 was the first firearm manufactured by Smith & Wesson, with production spanning the years 1857 through 1882. It was the first commercially successful revolver to use metallic rimfire cartridges instead of loose powder, musket ball, and percussion caps. It is a single-action, tip-up revolver holding seven .22 Short black powder cartridges. The Smith & Wesson Model No. 2 Army is a 6-shot, .32 caliber revolver, intended to combine the small size and convenience of the Smith & Wesson Model 1 .22 rimfire with a larger more effective cartridge. It was manufactured 1861–1874, with a total production of 77,020 units. The Smith & Wesson Model 3 was a 6-shot, single-action, cartridge-firing, top-break revolver produced by Smith & Wesson from circa 1870 to 1915, and was recently offered again as a reproduction by Smith & Wesson and Uberti. The S&W Model 3 was originally chambered for the .44 S&W American and .44 Russian cartridges, and typically did not have the cartridge information stamped on the gun (as is standard practice for most commercial firearms). Model 3 revolvers were later produced in an assortment of calibers, including .44 Henry Rimfire, .44-40, .32–44, .38–44, and .45 Schofield. The design would influence the smaller S&W .38 Single Action that is retroactively referred to as the Model 2. All of these revolvers would automatically eject the spent shell cases when opened. The Colt Single Action Army, also known as the Single Action Army, SAA, Model P, Peacemaker, M1873, and Colt .45 is a single-action revolver with a revolving cylinder holding six metallic cartridges. It was designed for the U.S. government service revolver trials of 1872