Informative read about the Battle of Antietam prepared as a “Staff Ride Guide” by Ted Ballard, CENTER OF MILITARY HISTORY, UNITED STATES ARMY. This assisted, among other things, with my understanding of artillery and particularly how units were organized who supported the guns. Interesting factoids from page 83 -84 (note this entire book is available online by clicking on the book image above):
“The artillery of both armies was generally organized into batteries of four or six guns. Regulations prescribed a captain as battery commander, while lieutenants commanded two-gun “sections.” Each gun made up a platoon, under a sergeant (“chief of the piece”) with eight crewmen and six drivers.
For transport, each gun was attached to a two-wheeled cart, known as a limber and drawn by a six-horse team. The limber chest carried thirty to fifty rounds of ammunition, depending on the size of guns in the battery. In addition to the limbers, each gun had at least one caisson, also drawn by a six-horse team. The caisson carried additional ammunition in two chests, as well as a spare wheel and tools. A horse-drawn forge and a battery wagon with tools accompanied each battery. A battery at full regulation strength included all officers, noncommissioned officers, buglers, drivers, cannoneers, and other specialized functions and might exceed 100 officers and men. With spare horses included, a typical six-gun battery might have 100-150 horses.
A battery could unlimber and fire an initial volley in about one minute, and each gun could continue firing two aimed shots a minute. A battery could “limber up” in about one minute as well. The battery practiced “direct fire”: the target was in view of the gun. The prescribed distance between guns was fourteen yards from hub to hub. Therefore, a six-gun battery would represent a front of about 100 yards. Depth of the battery position from the gun muzzle, passing the limber, to the rear of the caisson was prescribed as forty-seven yards. In practice, these measurements might be altered by terrain.”