On August 8, 1854, Smith & Wesson patented metal bullet cartridges. From the article:
"The American role in metallic cartridges began with Walter Hunt, the inventor of the safety pin and fountain pen, who patented his "rocket ball." The rocket ball was a conical bullet that encased its powder and blocked the bottom of the bullet with a cork or paper wad. Yet, priming was still separate and supplied through a fulminate “‘pill’ that fed into the action automatically as the cartridge was chambered."5 However his ammunition and rifle, the Volition Repeater, would never become widely popular, and nor would the guns that directly followed the Volition Repeater due to their imperfection or over-complexity.6
The predecessor to the American-made rim-fire metallic cartridge was a bullet that had a hollow base with fulminate priming in it, and it was made by Horace Smith, Daniel Wesson, and Oliver Winchester in the early 1850s.7 Americans Horace Smith and Daniel Wesson patented improvements to the Flobert1 cartridge on August 8, 1854. Their improvement "spread primer across the base of the cartridge and tallow lubricant behind the ball."8 That bullet helped to guide the course of ammunition modernization, including the move to the rim-fire metallic cartridge.
Rim-fire quickly evolved from the first metallic cartridges. The primer, usually fulminate, was located around the rim that was attached to the bottom of the cartridge. When the hammer hit the rim of the cartridge, it would spark and set off the powder charge in the cartridge.9 Those cartridges were made out of copper or brass and formed a gas seal for the ignition chamber after it expanded during the ignition explosion.10 After the led bullet was fired, the cartridges then would contract as they cooled down after the explosion, allowing for the marksman to easily extract the cartridges.9 That method proved to be very effective for breechloaders.
Benjamin Tyler Henry, who worked for Smith & Wesson before his work with the New Haven Arms Company where he invented his repeating rifle, was a pioneer that led the way in the development of the metallic self-contained cartridge.11 The Henry cartridge was a .44 caliber rim-fire with 26 grains of powder, and included a 216-grain bullet.12 He patented his rifle and cartridge on October 16, 1860. (The Henry Rifle, however, was never truly mass produced in large numbers during the Civil War; therefore, it was not as widely used as the Spencer.13"