Field artillery in the American Civil War

Field artillery in the American Civil War refers to the important artillery weapons, equipment, and practices used by the Artillery branch to support the infantry and cavalry forces in the field. It does not include siege artillery, use of artillery in fixed fortifications, or coastal or naval artillery. Nor does it include smaller, specialized artillery termed as small arms.

Weapons
The principal guns widely used in the field are listed in the following table.

There were two general types of artillery weapons used during the Civil War: smoothbores and rifles. Smoothbores included howitzers and guns.

Smoothbores
Smoothbore artillery refers to weapons that are not rifled. At the time of the Civil War, metallurgy and other supporting technologies had just recently evolved to a point allowing the large scale production of rifled field artillery. As such, many smoothbore weapons were still in use and production even at the end of the war. Smoothbore field artillery of the day fit into two role-based categories: guns and howitzers. Further classifications of the weapons were made based on the type of metal used, typically bronze or iron (cast or wrought), although some examples of steel were produced. Additionally, the artillery was often identified by the year of design in the Ordnance department references.

The smoothbore artillery was also categorized by the bore dimensions, based on the rough weight of the solid shot projectile fired from the weapon. For instance a 12-pounder field gun fired a 12 pound solid shot projectile from its 4.62 in diameter bore. It was practice, dating back to the 18th century, to mix gun and howitzers into batteries. Pre-war allocations called for 6-pounder field guns matched with 12-pounder howitzers, 9 and 12-pounder field guns matched with 24-pounder howitzers. But the rapid expansions of both combatant armies, mass introduction of rifled artillery, and the versatility of the 12-pounder "Napoleon" class of weapons all contributed to a change in the mixed battery practices.

Guns
Smoothbore guns were designed to fire solid shot projectiles at high velocity, over low trajectories at targets in the open, although shot and canister were acceptable for use. The barrels of the guns were longer than corresponding howitzers, and called for higher powder charges to achieve the desired performance. Field guns were produced in 6-pounder (3.67 inch bore), 9-pounder (4.2 inch bore), and 12-pounder (4.62 inch bore) versions. Although some older iron weapons were pressed into service, and the Confederacy produced some new iron field guns, most of those used on the battlefields were of bronze construction.

The 6-pounder field gun was well represented by bronze Models of 1835, 1838, 1839, and 1841 early in the war. Even a few older iron Model of 1819 weapons were pressed into service. Several hundred were used by the armies of both sides in 1861. But in practice the limited payload of the projectile was seen as a shortcoming of this weapon. From mid-war on, few 6-pounders saw action in the main field armies.

The larger 9- and 12-pounders were less well represented. While the 9-pounder was still listed on Ordnance and Artillery manuals in 1861, very few were ever produced after the War of 1812 and only scant references exist to Civil War use of the weapons. The 12-pounder field gun appeared in a series of models mirroring the 6-pounder, but in far less numbers. At least one Federal battery, the 13th Indiana, took the 12-pounder field gun into service early in the war. The major shortcoming of these heavy field guns was mobility, as they required eight-horse teams as opposed to the six-horse teams of the lighter guns. A small quantity of 12-pounder field guns were rifled early in the war, but these were more experimental weapons, and no field service is recorded.

By far the most popular of the smoothbore cannon was the 12-pounder Model of 1857, Light, commonly called "Napoleon". The Model 1857 was of lighter weight than the previous 12-pounder guns, and could be pulled by a six-horse draft, yet offered the heavier projectile payload of the larger bore. It is sometimes called, confusingly, a "gun-howitzer" (because it possessed characteristics of both gun and howitzer) and is discussed in more detail separately below.

Howitzers
Howitzers were short-barreled guns that were optimized for firing explosive shells in a high trajectory, but also for spherical case shot and canister, over a shorter range than the guns. While field use alluded to firing at targets consisting of enemy forces arrayed in the open, howitzers were considered the weapon of choice if the opposing forces were concealed behind terrain features or fortifications. Howitzers used lower powder charges than guns of corresponding caliber. Field Howitzer calibers used in the Civil War were 12-pounder (4.62 inch bore), 24-pounder (5.82 inch bore), and 32-pounder (6.41 inch bore). Most of the howitzers used in the war were bronze, with notable exceptions of some of Confederate manufacture.

Coupled to the 6-pounder field gun in allocations of the pre-war Army, the 12-pounder field Howitzer was represented by Models of 1838 and 1841. With a light weight and respectable projectile payload, the 12-pounder was only cycled out of the main field army inventories as production and availability of the 12-pounder "Napoleon" rose, and would see action in the Confederate armies up to the very end.

As with the corresponding heavy field guns, the heavier Howitzers were available in limited quantities early in the war. Both Federal and Confederate contracts list examples of 24-pounders delivered during the war, and surviving examples exist of imported Austrian types of this caliber used by the Confederates. These 24-pounder Howitzers found use in the "reserve" batteries of the respective armies, but were gradually replaced over time with heavy rifled guns. Both the 24- and 32-pounders were more widely used in fixed fortifications, but at least one of the later large weapons was with the 1st Connecticut Artillery as late as 1864.

Finally, the lesser known but highly-mobile 12-pounder mountain Howitzer saw service with infantry and cavalry forces in the rugged western theaters and prairies, and continued in service during the Indian Wars. This versatile piece could utilize one of two carriages: a small carriage that could be drawn by a single animal or could be rapidly broken down to carry on the backs of pack animals, or a slightly larger prairie carriage to be drawn by two animals. A veteran of the Mexican-American War, several hundred more of these diminutive tubes were produced by Union foundries during the Civil War, and the Confederate Tredegar foundry turned out as many as 21 more. A Federal battery of four proved "highly effective" at the decisive battle of Glorieta, New Mexico, and Nathan Bedford Forrest frequently employed mountain howitzers for the rapid close-in combat that he favored.

12-pounder Napoleon
The twelve-pound cannon "Napoleon" was the most popular smoothbore cannon used during the war. It was named after Napoleon III of France and was widely admired because of its safety, reliability, and killing power, especially at close range. In Union Ordnance manuals it was referred to as the "light 12-pounder gun" to distinguish it from the heavier and longer 12 pounder gun (which was virtually unused in field service.) It did not reach America until 1857. It was the last cast bronze gun used by an American army. The Federal version of the Napoleon can be recognized by the flared front end of the barrel, called the muzzle-swell. It was, however, relatively heavy compared to other artillery pieces and difficult to move across rough terrain.

Confederate Napoleons were produced in at least six variations, most of which had straight muzzles, but at least eight catalogued survivors of 133 identified have muzzle swells. Additionally, four iron Confederate Napoleons produced by Tredegar Iron Works in Richmond have been identified, of an estimated 125 cast. In early 1863 Robert E. Lee sent nearly all of the Army of Northern Virginia's bronze 6-pounder guns to Tredegar to be melted down and recast as Napoleons. Copper for casting bronze pieces became increasingly scarce to the Confederacy throughout the war and became acute in November 1863 when the Ducktown copper mines near Chattanooga were lost to Union forces. Casting of bronze Napoleons by the Confederacy ceased and in January 1864 Tredegar began producing iron Napoleons.

Rifled guns
Rifling adds spiral grooves along the inside of the gun barrel for the purpose of spinning the shell or shot and enacting gyroscopic force that increases the accuracy of the gun by preventing the shell from rotating along axes other than the axis parallel to the gun barrel. Adding rifling to a gun tube made it more difficult and expensive to manufacture and increased the length of the tube, but it increased the range and accuracy of the piece. While most of the rifled guns in the Civil War were muzzle-loaded, a small number of breech-loaded guns were used.

3-inch rifle
The 3 in rifle was the most widely used rifled gun during the war. Invented by John Griffen, it was extremely durable, with the barrel made of wrought iron, primarily produced by the Phoenix Iron Company of Phoenixville, Pennsylvania. There are few cases on record of the tube fracturing or bursting, a problem that plagued other rifles made of brittle cast iron. The rifle had exceptional accuracy. During the Battle of Atlanta, a Confederate gunner was quoted: "The Yankee three-inch rifle was a dead shot at any distance under a mile. They could hit the end of a flour barrel more often than miss, unless the gunner got rattled." The 1st Minnesota Light Artillery Battery converted into the 3-inch Rifle on 5 March 1864, though they were considered "3-inch Rodman's guns" in a 11 Nov. 1864 letter from 1st Lieutenant Henry S. Hurter to the Minnesota Adjutant General. The 1st Minnesota Light Artillery took part in the Atlanta Campaign.

Parrott rifles
The Parrott rifle, invented by Robert Parker Parrott, was manufactured in different sizes, from 10-pounders up to the rare 300-pounder. The 10- and 20-pounder versions were used by both armies in the field. The smaller size was much more prevalent; it came in two bore sizes: 2.9 in and 3.0 in. Confederate forces used both bore sizes during the war, which added to the complication of supplying the appropriate ammunition to its batteries. Until 1864, Union batteries used only the 2.9 inch Parrott, but they also employed 3" Ordnance rifles. During the 1st day of Gettysburg, three Parrott rifles were temporarily unusable when 3" ammunition was issued to the battery by mistake. Following this plans were made to re-rifle all of the 2.9" Parrotts to 3", so as to standardize ammunition and no further 2.9" Parrotts were to be produced. The M1863, with a 3 in bore, had firing characteristics similar to the earlier model; it can be recognized by its straight barrel, without muzzle-swell.

Parrotts were manufactured with a combination of cast iron and wrought iron. The cast iron improved the accuracy of the gun but was brittle enough to suffer fractures. On the Parrott, a large wrought iron reinforcing band was overlaid on the breech. Although accurate, the Parrott had a poor reputation for safety, and they were shunned by many artillerymen. (At the end of 1862, Henry J. Hunt attempted to get the Parrott eliminated from the Army of the Potomac's inventory.) The 20-pounder was the largest field gun used during the war, with the barrel alone weighing over 1,800 pounds (800 kg).

James rifles


James rifles were an early solution to the need for rifled artillery at the start of the war. 6-pounder bronze guns could be rifled to fire the projectiles invented by Charles T. James. Some were simply rifled from their initial 3.67" bore, others were reamed to 3.80" then rifled. Reaming to 3.80" was preferred to eliminate wear deformities from service. Nomenclature for the two sizes could be muddled and varied, but the effective descriptions for the 3.67" are "rifled 6-pounder" or "12-pounder James rifle", while the 3.80" variant was known as the 14-pounder James rifle.  To add to the confusion new bronze (and a few iron) variants of the 3.80" bore rifle (14-pounder James rifle) were also produced with a longer, heavier tube utilizing the Ordnance profile.

Although the James rifles were reported to be extremely accurate, bronze rifling wears rapidly and the James rifles and projectiles soon fell out of favor. No new James rifles were known to have been produced after 1862. The total numbers of James rifles are uncertain, but the 1862 Ohio Quartermaster General annual report recorded 82 rifled bronze pieces (44 of those specified as "3.80 bore [James rifles]") out of a total of 162 of all field artillery types. Unusual or out of favor types migrated to the Western theaters.



Whitworth
The Whitworth, designed by Joseph Whitworth and manufactured in England, was a rare gun during the war, but was an interesting precursor to modern artillery in that it was loaded from the breech and had exceptional accuracy over great distance. An engineering magazine wrote in 1864 that, "At 1600 yards [1500 m] the Whitworth gun fired 10 shots with a lateral deviation of only 5 inches." This degree of accuracy made it effective in counter-battery fire, used almost as the equivalent of a sharpshooter's rifle, and also for firing over bodies of water. It was not popular as an anti-infantry weapon. It had a caliber of 2.75 in. The bore was hexagonal in cross-section, and the projectile was a long bolt that twisted to conform to the rifling. It is said that the bolts made a very distinctive eerie sound when fired, which could be distinguished from other projectiles.

Ammunition
Ammunition came in wide varieties, designed to attack specific targets. A typical Union artillery battery (armed with six 12-pounder Napoleons) carried the following ammunition going into battle: 288 shot, 96 shells, 288 spherical cases, and 96 canisters.

Shot (or bolt)
Shot was a solid projectile that included no explosive charge. For a smoothbore, the projectile was a round "cannonball". For a rifled gun, the projectile was referred to as a bolt and had a cylindrical or spherical shape. In both cases, the projectile was used to impart kinetic energy for a battering effect, particularly effective for the destruction of enemy guns, limbers and caissons, and wagons. It was also effective for mowing down columns of infantry and cavalry and had psychological effects against its targets. Despite its effectiveness, many artillerymen were reluctant to use solid shot, preferring the explosive types of ordnance. With solid projectiles, accuracy was the paramount consideration, and they also caused more tube wear than their explosive counterparts.

While rifled cannon had much greater accuracy on average than smoothbores, the smoothbores had an advantage firing round shot relative to the bolts fired from rifled pieces. Round shot could be employed in ricochet or rolling fire extending the depth and range of its effect on land or water while bolts tended to dig in rather than ricochet.

Shell
Shells included an explosive charge and were designed to burst into fragments in the midst of enemy infantry or artillery. For smoothbores, the projectile was referred to as "spherical shell". Shells were more effective against troops behind obstacles or earthworks, and they were good for destroying wooden buildings by setting them on fire. They were ineffective against good quality masonry. A primary weakness of shell was that it typically produced only a few large fragments, the count increasing with caliber of the shell. A Confederate mid-war innovation perhaps influenced by British ordnance/munition imports was the "polygonal cavity" or "segmented" shell which used a polyhedral cavity core to create lines of weakness in the shell wall that would yield more regular fragmentation patterns—typically 12 similarly sized fragments. While segmented designs were most common in spherical shell, it was applied to specific rifled projectiles as well.

Spherical shell used time fuses, while rifled shell could use timed fuse or be detonated on impact by percussion fuse. Fuse reliability was a concern; any shell that buried itself into the earth before detonating had little anti-personnel effectiveness. However, large caliber shells, such as the 32-pounder spherical were effective at breaching entrenchments.

Case (or shrapnel)
Case (or "spherical case" for smoothbores) were anti-personnel projectiles carrying a smaller burst charge than shell, but designed to be more effective against exposed troops. While shell produced only a few large fragments, case was loaded with lead or iron balls and was designed to burst above and before the enemy line, showering down many more small but destructive projectiles on the enemy. The effect was analogous to a weaker version of canister. With case the lethality of the balls and fragments came from the velocity of the bursting projectile itself&mdash;the small burst charge only fragmented the case and dispersed the shrapnel. The spherical case used in a 12-pounder Napoleon contained 78 balls. The name shrapnel derives from its inventor, Henry Shrapnel.

The primary limitations to case effectiveness came in judging the range, setting the fuse accordingly, and the reliability and variability of the fuse itself.

Canister
Canister shot was the deadliest type of ammunition, consisting of a thin metal container loaded with layers of lead or iron balls packed in sawdust. Upon exiting the muzzle, the container disintegrated, and the balls fanned out as the equivalent of a shotgun blast. The effective range of canister was only 400 yd, but within that range dozens of enemy infantrymen could be mowed down. Even more devastating was "double canister", generally used only in dire circumstances at extremely close range, where two containers of balls were fired simultaneously.

Grapeshot
Grapeshot was the predecessor of, and a variation on, canister, in which a smaller number of larger metal balls were arranged on stacked iron plates with a threaded bolt running down the center to hold them as a unit inside the barrel. It was used at a time when some cannons burst when loaded with too much gunpowder, but as cannons got stronger, grapeshot was replaced by canister. A grapeshot round (or "stand") used in a 12-pounder Napoleon contained 9 balls, contrasted against the 27 smaller balls in a canister round. By the time of the Civil War, grapeshot was obsolete and largely replaced by canister. The period Ordnance and Gunnery work states that grape was excluded from "field and mountain services." Few, if any, rounds were issued to field artillery batteries.

Equipment
The most pervasive piece of artillery equipment was the horse.

Horse
Horses were required to pull the enormous weight of the cannon and ammunition; on average, each horse pulled about 700 pounds (317.5 kg). Each gun in a battery used two six-horse teams: one team pulled a limber that towed the gun, the other pulled a limber that towed a caisson. The large number of horses posed a logistical challenge for the artillery, because they had to be fed, maintained, and replaced when worn out or injured. Artillery horses were generally selected second from the pool of high quality animals; cavalry mounts were the best horses. The life expectancy of an artillery horse was under eight months. They suffered from disease, exhaustion from long marches&mdash;typically 16 miles (25.8 km) in 10 hours&mdash;and battle injuries.

Horses were larger and stupider than men when subjected to counter-battery fire, and their movements were made difficult because they were harnessed together into teams. Robert Stiles wrote about Union fire striking a Confederate battery on Benner's Hill at the Battle of Gettysburg:

"Such a scene as it presented&mdash;guns dismounted and disabled, carriages splintered and crushed, ammunition chests exploded, limbers upset, wounded horses plunging and kicking, dashing out the brains of men tangled in the harness; while cannoneers with pistols were crawling around through the wreck shooting the struggling horses to save the lives of wounded men."

The term "horse artillery" refers to the faster moving artillery batteries that typically supported cavalry regiments. The term "flying artillery" is sometimes used as well. In such batteries, the artillerymen were all mounted, in contrast to batteries in which the artillerymen walked alongside their guns. A prominent organization of such artillery in the Union Army was the U.S. Horse Artillery Brigade.



Limber
The limber was a two-wheeled carriage that carried an ammunition chest. It was connected directly behind the team of six horses and towed either a gun or a caisson. In either case, the combination provided the equivalent of a four-wheeled vehicle, which distributed the load over two axles but was easier to maneuver on rough terrain than a four-wheeled wagon. The combination of a Napoleon gun and a packed limber weighed 3,865 pounds (1,753.1 kg).

Caisson
The caisson was also a two-wheeled carriage. It carried two ammunition chests and a spare wheel. A fully loaded limber and caisson combination weighed 3,811 pounds (1728.6 kg).

The limbers, caissons, and gun carriages were all constructed of oak. Each ammunition chest typically carried about 500 pounds (226.8 kg) of ammunition or supplies. In addition to these vehicles, there were also battery supply wagons and portable forges that were used to service the guns.

Union artillery
The Union Army entered the war with a strong advantage in artillery. It had ample manufacturing capacity in Northern factories, and it had a well-trained and professional officer corps manning that branch of the service. Brig. Gen. Henry J. Hunt, who was the chief of artillery for the Army of the Potomac for part of the war, was well recognized as a most efficient organizer of artillery forces, and he had few peers in the practice of the sciences of gunnery and logistics. Another example was John Gibbon, the author of the influential Artillerist's Manual published in 1863 (although Gibbon would achieve considerably more fame as an infantry general during the war). Shortly after the outbreak of war, Brig. Gen. James Wolfe Ripley, Chief of Ordnance, ordered the conversion of old smoothbores into rifled cannon and the manufacture of Parrott guns.

The basic unit of Union artillery was the battery, which usually consisted of six guns. Attempts were made to ensure that all six guns in a battery were of the same caliber, simplifying training and logistics. Each gun, or "piece", was operated by a gun crew of eight, plus four additional men to handle the horses and equipment. Two guns operating under the control of a lieutenant were known as a "section". The battery of six guns was commanded by a captain. Artillery brigades composed of five batteries were commanded by colonels and supported the infantry organizations as follows: each infantry corps was supported directly by one artillery brigade and, in the case of the Army of the Potomac, five brigades formed the Artillery Reserve. This arrangement, championed by Hunt, allowed artillery to be massed in support of the entire army's objective, rather than being dispersed all across the battlefield. An example of the tension between infantry commanders and artillery commanders was during the massive Confederate bombardment of Cemetery Ridge on 3 July 1863, the third day of the Battle of Gettysburg. Hunt had difficulty persuading the infantry commanders, such as Maj. Gen. Winfield S. Hancock, against using all of their artillery ammunition in response to the Confederate bombardment, understanding the value to the defenders of saving the ammunition for the infantry assault to come, Pickett's Charge.

At the start of the war, the U.S. Army had 2,283 guns on hand, but only about 10% of these were field artillery pieces. By the end of the war, the army had 3,325 guns, of which 53% were field pieces. The army reported as "supplied to the army during the war" the following quantities: 7,892 guns, 6,335,295 artillery projectiles, 2,862,177 rounds of fixed artillery ammunition, 45,258 tons of lead metal, and 13,320 tons of gunpowder.

Confederate artillery
The South was at a relative disadvantage to the North for deployment of artillery. The industrial North had far greater capacity for manufacturing weapons, and the Union blockade of Southern ports prevented many foreign arms from reaching the Southern armies. The Confederacy had to rely to a significant extent on captured Union artillery pieces (either on the battlefield or by capturing armories, such as Harpers Ferry); it is estimated that two-thirds of all Confederate field artillery was captured from the Union. The Confederate cannons built in the South often suffered from the shortage of quality metals and shoddy workmanship. Another disadvantage was the quality of ammunition. The fuses needed for detonating shells and cases were frequently inaccurate, causing premature or delayed explosions. All that, coupled with the Union gunners' initial competence and experience gained as the war progressed, led Southern forces to dread assaults on Northern positions backed up by artillery. A Southern officer observed, "The combination of Yankee artillery with Rebel infantry would make an army that could be beaten by no one."

Confederate batteries usually consisted of four guns, in contrast to the Union's six. This was a matter of necessity, because guns were always in short supply. And, unlike the Union, batteries frequently consisted of mixed caliber weapons. Confederate batteries were generally organized into battalions (versus the Union brigades) of four batteries each, and the battalions were assigned to the direct support of infantry divisions. Each infantry corps was assigned two battalions as an Artillery Reserve, but there was no such Reserve at the army level. The chief of artillery for Robert E. Lee's Army of Northern Virginia, Brig. Gen. William N. Pendleton, had considerable difficulty massing artillery for best effect because of this organization. {{Hide in print|1=

Battles
Although virtually all battles of the Civil War included artillery, some battles are known better than others for significant artillery engagements, arguably critical to the overall outcome:


 * Battle of Antietam
 * Battle of Chancellorsville
 * Battle of Stones River
 * Battle of Fredericksburg
 * Battle of Gettysburg
 * Battle of Malvern Hill
 * Battle of Nashville

Civil War artillerists
Not nearly as well known as their infantry and cavalry counterparts, a small group of officers excelled at artillery deployment, organization, and the science of gunnery:


 * Edward Porter Alexander
 * Thomas H. Carter
 * Alonzo Cushing
 * John Gibbon (Artillerist's Manual)
 * Henry Jackson Hunt
 * Stonewall Jackson (artillery instructor before the war)
 * Joseph W. Latimer
 * Freeman McGilvery
 * "Willy" Pegram
 * John Pelham
 * William N. Pendleton
 * Charles S. Wainwright
 * Reuben Lindsay Walker

Civil War artillery organizations

 * Danville Artillery
 * Fluvanna Artillery
 * Washington Artillery