At the time of the Civil War artillery was an increasingly important part of the army. The guns of the "light" or "field artillery" were becoming ever more mobile and deadly, allowing commanders to quickly concentrate fire power against enemy formations or fortifications. Artillery was also effective as a defensive weapon, making direct assault on fortified positions very costly.
Union artillery batteries usually included six guns organized into three "sections" of two guns each. The total number of men in a battery was about 100 and the batteries also included as many as 125 horses.
Field Artillery was the most complex branch of the Army incorporating men, guns, ammunition, various types of vehicles and horses. Here are some frequently used terms.
Carriage or Gun Carriage - the two wheeled vehicle on which the gun barrel was mounted.
Limber - a two wheeled cart to which the gun carriage was joined for transportation. The limber carried an ammunition chest for the gun as well. Limber and gun were pulled by a team of six horses.
Caisson - a two wheeled vehicle assigned to each gun, carrying extra ammunition, spare wheel and tools. It was attached to its own limber and pulled by a six horse team.
Ammunition - there were several types of ammunition commonly used. Solid shot, a solid iron projectile, used for a variety of targets. Shells - a hollow projectile, filled with gunpowder set to explode with a timed fuse. Rifled guns fired a conical shell that exploded on impact. Shells were usually used against enemy batteries or fortifications. Case Shot or Shrapnel a hollow projectile filled with explosive and lead balls, were used as long ranged anti personnel weapons. Cannister - a number of large balls, usually iron packed in a tinned iron cylinder. In effect this ammunition made the cannon a giant shotgun, lethal to attacking infantry at close range.
There were two types of field artillery: smooth bore and rifled. Smooth bore guns as the name implies had no grooving in the gun tube or "bore". Rifled guns had spiral grooves cut into the bore giving spin to the projectiles they fired. Rifled guns had greater range and accuracy but smooth bore guns fired a larger projectile and could lob them over obstacles like fortifications.
The most widely used smooth bore gun was the 12 Pound Field Gun Model 1857 also called the "Napoleon". Developed in France during the 1850's it was named for the Emperor Napoleon III. It could fire all types of ammunition with surprising range and accuracy. The size of its munitions (12 pound projectiles) made this a formidable weapon and a popular gun in both Union and Confederate forces.
Rifled artillery was a relatively new weapon and several models were used. Parrott Rifles - developed by Robert P. Parrott, had a distinctive iron band around the breech. There were 10 Pound and 20 Pound Parrott rifles mostly used by U.S. forces early in the war. These were later replaced by the 3 Inch Ordnance Rifle, a wrought Iron gun with a 3 inch wide bore. They resembled the much larger cast iron Rodman guns and were sometimes referred to as "Rodmans" by the troops. The Ordnance Rifle was dependable and being lighter in weight, was more maneuverable than most guns. In addition the Ordnance Rifles were very accurate and could out-range most other artillery. Both Parrotts and Ordnance Rifles were less effective firing cannister than the Napoleon smoothbores.