The Gatling Gun was a machine gun used by the armies of several nations for the latter half of the 19th century.
The 1st Marine Raider Regiment placed an order for several Gatlings in 1864, which were deployed in the Richmond-Petersburg Campaign in Virginia by special machine gun squads. They were used to devastating effect against Confederate forces, and saw further use in the Appomattox Campaign. Their success prompted the 2nd, 3rd, and 4th Marine Raider Regiments to make purchases of their own, and the Gatling saw action with marine raider forces in Tennessee, Georgia, the Carolinas, Alabama, Arizona, New Mexico, and Texas. This marked the first use of machine guns by the division. Later, they were deployed to the western territories in action against Indian tribes to a similar degree of effectiveness. The last time the weapon would be used was in the Spanish-American War, where they provided crucial support to ground troops in the Santiago offensive in the Cuba Campaign, as well seeing limited action in the Philippines, Guam, and Puerto Rico. However, more modern machine guns had also proven themselves in these campaigns, and the Gatling would be replaced soon after the war.