A "cannon" is a large military engine for throwing projectiles by the force of gunpowder. This is a generic term that encompasses guns, howitzers, and mortars as defined below.
A "piece" refers to a single item of military ordinance. This too is a generic term and encompasses both cannons and other military ordinance, such as muskets and revolvers.
Guns, howitzers, and mortars are distinct types of cannons, generally classified on the basis of the relationship of the length of the barrel to the caliber, or bore diameter, of the cannon.
A "gun" has the longest barrel, relative to the caliber, and hence has the highest velocity and the flattest trajectory. Generally the gun has a barrel length greater than 25 times the bore diameter. A longer barrel allows the powder burn more time to accelerate the projectile, resulting in higher muzzle velocity. Guns are fairly common in civil war reenacting. For example, 1st Michigan Light Artillery's Parrott rifle is a gun.
A "howitzer" has a barrel length from 15 to 25 times the bore diameter and shoots at a higher trajectory than a gun. A "mountain howitzer" is designed to be quickly broken down for transportion by horseback. Howitzers are the most common type of cannon seen at civil war reenactments. Keystone Battery A has a mountain howitzer.
A "mortar" has barrel length less than 15 times the bore diameter, shoots at high trajectories and was used to loft its projectiles to the target. Mortars are fairly rare at civil war reenactments.
The field artillery (or light artillery) is composed of those artillery batteries that manuever with the troops on the field of battle. A "battery" is a group of cannons, with attendant men and equipment, which are organized together as a unit. Union batteries were usually composed of six cannons, but four cannon batteries were common and most Confederate batteries were made up of four cannons. The field artillery is divided into two parts - HORSE ARTILLERY, which is generally attached to and manuevers with cavalry, the cannoneers being mounted on horseback; and MOUNTED ARTILLERY, which is generally attached to and manuevers with infantry, the cannoneers marching at the sides of their pieces.
A field artillery piece consists of two major assemblies: the barrel and the carriage.
A civil war barrel would be made of cast iron or cast bronze. Modern reproduction barrels often are made with modern materials, such as steel-sleeved bores, and are safer than the civil war originals they resemble. Modern reproduction barrels are safer because modern materials and construction can withstand far higher pressures than the original cast material and that, combined with much lower powder charges used in reenacting, makes the risk of barrel failure negligible.
The barrel terminology that cannoneers must be familiar with include the muzzle, muzzle face, bore, chamber, vent, breech, cascable, and trunnions.
The carriage on which the barrel is mounted is designed for both holding and aiming the barrel and transporting it. Carriages were made of wood with metal hardware. White oak was the wood most often used but other hardwoods were used as well.
The "trail" is the wooden assembly running from the axle to the rear of the carriage. The trail is mounted to the "axle body", made of wood, which contains the "axle tree", made of metal within it. The "wheels" are connected to the axle tree.
The barrel is mounted on the carriage as follows: a heavily reinforced portion of the trail called the "cheek" has a metal strap fitting called the "trunnion plate" mounted to it … the trunnions of the barrel fit into the trunnion plates and are secured to the cheeks by the "cap squares". The barrel is able rotate on the trunnion axis in a vertical plane. The barrel is supported at the breech end by the "elevating screw" mounted in the trail. The barrel is thus supported at three points by the carriage.
The rear end of the trail is reinforced by a metal "trail plate" and terminates at the "lunette", a heavy iron ring. The lunette forms part of the pintle hitch arrangement that is used to connect the carriage to a limber for transportation.
"Trail handles" are located near the end of the trail to facilitate lifting and manuevering the trail. Fittings (the "large pointing ring" and the "small pointing ring") are provided for a wooden bar, called the "hand spike", which allows the trail orientation (for aiming) to be adjusted with additional leverage. "Prolonge hooks" hold a "prolonge" in place when not needed. The prolonge is a rope occasionally used for towing or braking the carriage when moving.
Carriage wheels consist of four main parts. The "tire" is an iron band around the circumference of the wheel. "Felloes" are wooden semicircular pieces, usually six to a wheel, in which terminate the outer end of the "spokes", of which there are usually twelve. The inner ends of the spokes terminate in the "hub" assembly, which mounts on the axle tree and is secured thereto.