Horse Artillery, Part I

The mention of Company M, 2nd U.S. Artillery several times in the history of B Company, 6th US Cavalry brought the subject of horse artillery back to my mind. It’s a topic that I’ve considered writing about for quite some time, as the experiences of the horse artillery is intertwined with that of the cavalry units that they fought with. So we’ll spend the next several days discussing what horse artillery was and then examine two batteries of horse artillery who supported regular cavalry units, one from each theater.

Horse artillery, or flying artillery as it was also called early in the war, was a type of light, fast-moving and fast-firing artillery which provided highly mobile support to cavalry units. In a nutshell, the concept was that these units would be as mobile as the mounted units they supported, using speed and positioning to make up for the relatively small caliber of their guns. A close ancestor of today’s self-propelled artillery, the horse artillery consisted of light cannons attached to two-wheeled carriages called caissons or limbers which carried the cannon’s ammunition and equipment. The cannon’s crewmen rode the horses and the caissons during movement. In normal artillery units, the crewmen marched alongside of their cannon.

Once in position, horse artillery crews were trained to quickly dismount, deploy or "unlimber" their guns, then rapidly fire at the enemy. Ammunition for the horse artillery generally consisted of round shot, shells or grapeshot. They could then just as rapidly "limber-up" (reattach the guns to the caissons), remount, and be ready to move to a new position. It was highly versatile and supported cavalry units by disrupting enemy formations and dueling enemy artillery in an offensive role, while they often worked in concert with cavalry units to act as a rearguard to cover the retreat of other units. Mobility was key to their survival, as they rarely fought from prepared positions.

Horse artillery first rose to prominence during the Mexican War, where it played a decisive role in several key battles. During the Civil War, it was made up almost entirely of company-sized batteries from the regular army’s artillery regiments. In the eastern theater, these batteries were nominally assigned to the Army of the Potomac’s U.S. Horse Artillery Brigade, which was assigned to the Cavalry Corps. In actuality, however, the various batteries were detached to support cavalry brigades and divisions, and the entire brigade never fought together as an entire unit. In the western theater, horse artillery consisted of individual batteries loosely grouped and assigned to support cavalry brigades.

The next post will focus on the two most prevalent artillery canon used by the horse artillery, the 12-pounder Napoleon cannon and the 3-inch ordnance rifle.