During the years leading up to and during the American Civil War there were numerous advances in firearms technology. This article will focus on some of these advances, namely the inventions of the Minié ball, the Spencer and Henry repeating rifles, and the Gatling gun. Before the invention of the Minié bullet it was necessary for the bullet to be the same diameter as the barrel in order for it to engage the rifling. This made loading difficult and time-consuming because the bullet would have to be pushed down the barrel with some force. For this reason, muzzle-loading rifles had never seen any use in combat. The Minié ball, however, changed that. The Minié projectile had a diameter slightly smaller than the rifle barrel, was conical in shape, and contained an iron cap in its hollow base. When fired, the force of the expanding charge pushed the iron cap into the base of the projectile, thus causing the base to expand slightly and the rifling to engage. The Minié projectile, fired from a rifled musket, had an effective range of up to 250 yards, a major improvement over earlier muskets and ammunition. The Minié ball-firing rifled musket became the most common firearm used by both sides during the Civil War, and the Springfield Armory in Massachusetts produced nearly two million of them for the Union Army. (History.com, 2010)Christopher Spencer first patented his Spencer rifle in 1860. (Greener, 1910) Although his rifle was not technically the first repeating rifle because Samuel Colt had adapted his revolver system for the used as a rifle, it was much more efficient and safer than the Colt rifle. The Spencer rifle had a seven-round magazine in the stock, and the ammunition was loaded from the magazine in the... center of the paper... laid the foundation for the invention of more modern repeating weapons, and their mechanisms are in fact still in use in many modern civilian weapons. Modern versions of the Gatling gun, such as the .30 cal. The Dillon Aero mini gun and the 30mm GAU-8 on the Air Force's A-10 Warthog are still in common use in the Army today. Works Cited Davis, W. C. (1991). Weapons of the Civil War. The Mallard Press.Greener, W.W. (1910). The gun and its development. Bonanza Books.History.com, S. (2010). Gatling gun. Retrieved from History.com: http://www.history.com/topics/gatling-gunHistory.com, s. (2010). Minié ball. Retrieved from History.com: http://www.history.com/topics/american-civil-war/minie-ballHogg, IV (1987). Weapons of the Civil War. Military print. the Gatling gun. (2005, April 5). Retrieved from civilwarhome.com: http://www.civilwarhome.com/gatlinggun.htm