War planners of the American Civil War were not lost on the value of artillery in their respective campaigns involving the North (Union) and South (Confederacy). They both made equal use of smoothbore muzzle-loading cannon of various caliber that could engage troop concentrations and fortifications at range. Clearly the most popular of all the field artillery guns of the war became the Model 1857 "Napoleon" firing a 12-pound cannonball several thousand yards.
Prior to the age of the "rifled" cannon, the smoothbore cannon ruled the European battlescape. Smoothbore guns were simpler to produce in number yet devastatingly effective, particularly at close ranges. A rifled barrel allowed for more accuracy at range and went on to replace smoothbore gun types although they offered a slower rate-of-fire overall. Nevertheless, the Model 1857 "Napoleon" 12-Pounder was produced in the United States for the US military Army by several foundries and held origins in the French "Canon Obusier de 12" of 1853. Named after Emperor Napoleon III (nephew of famed general Napoleon I), the French weapon saw extensive service with the army of France throughout the Crimean War (1853-1856) and was of 122mm caliber firing a 4.1 kilogram projectile (either basic ball, shell or canister shot) out to 1,400 yards at 1,440 feet per second. The cannon was a complete system - a gun barrel fitted to a special mounting atop a two-wheeled carriage. Transport was principally by horse or pack animal though it could be repositioned by a crew of handlers over short distances as required.
The American Model 1857 "Napoleon" was the primary artillery field gun of the Civil War as both sides utilized the type in number, finding the weapon to be highly reliable and devastatingly effective at all ranges. Union production totaled 1,156 units whilst Confederate production reached 501 units and, in the case of the latter, Confederate forces sought to recover as many captured Union Model 1857 guns as possible due to manufacturing limitations of the South. For the Union Army, the Model 1857 was originally adopted to replace the existing inventory of Model 1841 "6-Pounder" Field Guns though both weapons remained in service for the duration of the war by necessity. Union versions were generally identified by their muzzle "swell" (a tapered shaping) while many Confederate examples were simpler in form, often doing away with the swell to save on material and expedite production. Some Confederate forms even appeared in brass or iron as dictated by need and available resources, though their brittle nature made them prone to bursting at the breech area (requiring use of a reinforcement band). At the Battle of Gettysburg alone, 142 of the available 360 Union cannons were of the Model 1857 Napoleon type.
Bronze was typically utilized in the manufacture of the Model 1857 barrel which incorporated both tin and copper and resulted in a relatively light and mobile artillery piece with the heavy hitting firepower of previous European designs. The bore diameter measured 4.62 inches with a 66-inch overall running length, alone weighing 1,230lbs. This required the use of a heavy-duty wheeled carriage system for local transport. Additionally, a two-wheeled "limber" cart was used to prop the support "legs" up for long-distance travel which, in effect, created a four-wheeled transport system. A "caisson" served to supply the needed ammunition types to the gunnery crew of seven men.
The Model 1857 was cleared to fire several ammunition types depending on the battlefield situation. Projectiles were named after their weight (as in "12-pounder" being a 12-pound cannonball) though this was not always followed explicitly - rifled cannon presented its own set of designation issues, beginning to fall more in line with bore diameters then shot weight.
The basic shot was the solid 12-pound ball which was nothing more than an iron sphere in breaking light fortification walls and obstructions as well as the occasional limb. Cannonballs could easily relieve a man of his legs, arms or head and do even more damage against a collection of riflemen at range. Iron cannonballs were certainly cost-effective to produce in the thousands and thusly appeared in great numbers in any war of the period - having been used for centuries prior. Another ammunition type was the explosive "shell" which incorporated a rather simple fuse timer used in detonating a metal casing (shell) into hundreds of airborne fragments after impact. The delay was based on the length of fuse used. Canister shot was more akin to a buckshot shotgun blast in which dozens of metal balls were sprayed out of the muzzle of the cannon, principally against infantry at short range. One type of popular canister shot was "Grape Shot" - more common in naval service than land - which included the metal ball inventory but lacked the all-containing case - the balls being joined together by metal or fabric links.
A base gunnery crew consisted was 7 men, each trained (when possible) in the task of the other and led by a gunner of (generally) corporal rank. The men in the gunnery team were numbered upwards from "1" to "7" and referred to as such during the loading, firing and reloading process by the commander. Artillery gunners were specially trained individuals with one of the harder battlefield roles of the time - often attempting to conduct their operations in the heat of battle, being exposed to the elements and enemy fire. Daily training was especially important for the group to function properly and effectively as a cohesive unit.
The gun would be brought to its general position by horse and limber to which then the limber was removed and the gun properly positioned at the required location. Crewman #3 managed his thumb over the firing vent to protect from accidental ignition of the charge, which was loaded prior to the shot. The primary gunner (corporal) would sight the weapon from behind (taking into account line of sight and range) and prompt the ammunition handlers to action (Crewman #6 and #7). The projectile was then prepared and (if applicable) the fuse set based on the required range before being handed to a runner (Crewman #5) who would bring the projectile to the front of the weapon. Crewman #2 then took the projectile and - following the already loaded charge - inserted the projectile into the muzzle of the weapon. Crewman #1 then rammed the projectile down the barrel using a long pole. Final aiming and elevation took place, the latter by way of an elevating screw. Once readied, the command was given to tear into the charge bag (Crewman #3) by inserting a metal pin into the firing vent. Crewman #4 then added a friction primer to the vent hole attached to a lanyard. Once the command of "fire" was shouted, Crewman #4 pulled the lanyard to which sparks ignited the charge bag and the resulting force sent the projectile out towards the target. Following the shot, Crewman #1 (with the rammer, doubling on one end as a swab) swabbed the barrel clean of any remaining burning embers, making it clear to fire again. The swab was wetted when possible to ensure all embers were dealt with. The process was repeated as many times as necessary during the course of a battle. With each successive shot, the cannon recoiled rearwards on its wheels, stopped by its weight and friction. As such, the cannon has to be moved back into position and re-sighted manually prior to firing.
A well-drilled and experienced crew of seven could manage up to four rounds per minute which, when tied to a full battery of guns, could project a most fantastic salvo onto the enemy force. Taking elevation and distance into account, the weapon would either increase or decrease in its overall lethality though effects on the target were generally good. Both sides respected the killing power of the Napoleon 12-pounder with no exceptions. Effective range was out to about 2,000 yards.
Bronze was the metal of choice for smoothbore cannon construction prior to "rifling" for bronze tended to be a softer metal, proving poor for making rifled cannon conversions. Iron made for a stronger natural alternative in rifled cannon though these designs tended to become brittle over time, requiring various reinforcement innovations to be utilized as stop-gap measures. Some late-war Model 1857s were indeed converted to rifled types though their original bronze fabrication made them poor alternatives to their iron counterparts. As such, the Model 1857 Napoleon became the last bronze gun adopted by the American Army.