The Civil War marked a dramatic turning point in the evolution of warfare. The years immediately preceding the war and the period of the conflict itself saw important advances in small arms, such as the rifle musket, the revolver, and the magazine rifle (also known as the repeater), as well as a huge array of innovations, including the use of balloons for reconnaissance, the first land mines and machine guns, and even the first military use of a primitive submarine. The telegraph, which had been invented by Samuel Morse just seventeen years before the war began, also played an important role in the formation and implementation of combat strategy. The telegraph allowed officers in the field to remain in close touch with their counterparts in other regions, and it also allowed combat officers to relay important information to their superiors in Washington and Richmond.

The impact of advances in small arms can't be overestimated. The rifle musket, which replaced the smoothbore musket as the most commonly used infantry weapon in the 1850s, marked the first improvement in shoulder arms in nearly 150 years. Because of their limitations, smoothbore muskets were most effective only in massed units, but the rifle musket offered a number of improvements that resulted in greater accuracy, distance, and ease of use.

Two entirely new types of firearms appeared during the Civil War: the breechloader and the magazine rifle. Breechloaders became safer and more effective during the Civil War, although they still saw limited use during the war because many ordnance officers thought the weapons were wasteful. The magazine rifle loaded from a “magazine,” which stored bullets on the rifle itself. One type, called the Henry Repeating Rifle, could fire twenty-eight shots a minute and was much favored by Union soldiers, who would buy them with their own pay.