M1841 12-pounder howitzer

At the beginning of the 19th century, armies employed field guns for direct artillery fire and mortars for high-angle fire. Intermediate between the field gun and mortar was the howitzer which launched an explosive shell on a curved trajectory against enemy personnel or fortifications. In general, a howitzer required a smaller charge than a field gun to lob a projectile of similar weight. Larger howitzers were often named after the size of the bore (or caliber), for example the 8-inch howitzer.[1] On the other hand, by British and American convention, some howitzers were named after the field gun which had the same bore size.[2] Therefore, in the US Army, the weapon was named the 12-pounder howitzer because it had the same bore size as the 12-pounder gun, which was 4.62 in (117 mm) in diameter. Since a smaller charge was needed to fire a projectile, the 12-pounder howitzer had a smaller chamber near the breech 3.67 in (93 mm) in diameter.[1]

Manufacture of bronze artillery pieces required copper and tin. Since the United States had few copper and no known tin deposits, in 1800 Secretary of War Henry Dearborn urged all cannons to be cast from iron. For two decades after the War of 1812 the United States failed to produce a reliable 6-pounder gun. In one lot of 86 cast iron guns, 21 burst at the first fire during testing. Consequently, the Ordnance Board of 1831 under Alexander Macomb specified that field artillery pieces should be manufactured from bronze. The 1834 regulations required that field guns be made in 6-, 9-, and 12-pounder calibers and howitzers in 12- and 24-pounder calibers. It was desired for the 12-pounder howitzer to fit the 6-pounder field gun carriage. After some experimentation, gun founders Cyrus Alger & Co. and N. P. Ames produced the successful bronze smoothbore M1841 6-pounder field gun.[3]

Cyrus Alger & Co. delivered 19 and N. P. Ames delivered 7 bronze Model 1835 12-pounder howitzers in 1837–38. The two companies produced 24 more bronze Model 1838 12-pounder howitzers in 1839–40. The Model 1835 was 53.0 in (1.35 m) in length and weighed 717 lb (325.2 kg) while the Model 1838 was 49.0 in (1.24 m) in length and weighed 690 lb (313.0 kg). During the period 1834–1841, Alger, Ames, the West Point Foundry, and the Columbia Foundry produced small numbers of cast iron versions, but no large contracts resulted.[4]

The final bronze Model 1841 12-pounder howitzers manufactured by Alger and Ames served the US Army for the next 27 years (i.e until 1868). The Model 1841 was 53.0 in (1.35 m) long and weighed 785 lb (356.1 kg). At least 251 Model 1841 12-pounder howitzers were produced by Alger, Ames, and other companies.[5] Ames and Alger each delivered their first 6 Model 1841 howitzers in October and November 1841.[6] The Eagle Foundry of Miles Greenwood in Cincinnati, Ohio produced 14 bronze M1841 12-pounder howitzers for the U.S. Army in 1861–62. The Western Foundry of William D. Marshall & Co. of St. Louis, Missouri delivered 16 bronze M1841 12-pounder howitzers to the U.S. Army during the same period.[7]

Several foundries in the Confederacy manufactured an estimated 118 bronze and 66 cast iron 12-pounder howitzers during the American Civil War. Leading all producers was the Tredegar Iron Works which delivered 42 bronze and 30 cast iron 12-pounder howitzers. Other Confederate producers of this weapon were Quinby and Robinson (43), T. M. Brennan (26), Noble Brothers (14), Leeds (9), John Clark (7), Washington Foundry (7), Wolff (3), A. B. Reading (2), and Skates (1).[8] The Confederate-made iron 12-pounder howitzer was several inches longer than the U.S. version and weighed 850 lb (385.6 kg).[9]

Note that the M1841 mountain howitzer was of the same 12-pounder caliber. The mountain howitzer was a much smaller weapon that made it highly mobile in rough terrain. However, because of its shorter range, the mountain howitzer filled only a minor role in the American Civil War, being used in the Western Theater.[10]

Confederate-made 12-pounder howitzer is displayed at Chickamauga and Chattanooga National Military Park.

The Model 1841 bronze 12-pounder howitzer barrel was 53.0 in (134.6 cm) from the base ring to the muzzle and weighed 785 lb (356 kg). The diameter of the bore (caliber) was 4.62 in (11.73 cm) and the bore length was 43.25 in (109.86 cm). This means the bore was 9.36 calibers long. The howitzer fired a 8.9 lb (4.0 kg) shell. At 5° elevation, the gun could throw the shell a distance of 1,072 yd (980 m) with the standard firing charge of 1.0 lb (0.45 kg).[11] Using a 1.0 lb. charge, the howitzer could hurl the shell a distance of 840 yd (768 m) at 3° elevation and 975 yd (892 m) at 4° elevation.[12] Canister shot was effective out to a distance of 350 yd (320 m). The 12-pounder spherical case shot (also called shrapnel) was loaded with 78 musket balls. The 12-pounder canister round contained 27 cast iron balls.[13]

A 6-pounder battery typically included four 6-pounder field guns and two 12-pounder howitzers. Altogether, the battery required fourteen 6-horse teams and seven spare horses.[14] The teams pulled the six artillery pieces and limbers, six caissons and limbers, one battery wagon, and one traveling forge. Each caisson carried two ammunition chests and each of the two limbers carried one, so that each gun was supplied with four ammunition chests.[15] The Union 1864 Field Artillery Instructions and the Confederate 1863 Ordnance Manual both prescribed that each ammunition chest held 15 shells, 20 spherical case shot, and 4 canister rounds. The total weights were as follows: shells 157.5 lb (71.4 kg), spherical case 273 lb (123.8 kg), and canister 47.4 lb (21.5 kg).[16] The carriage for both the 6-pounder gun and the 12-pounder howitzer weighed 900 lb (408 kg).[17] A gun crew consisted of one sergeant "chief-of-piece", two corporals, and six gunners. One gunner placed the projectile in the howitzer's muzzle while a second gunner rammed it home. Additionally, each gun had six drivers.[18]

Side view of a typical 19th-century smoothbore muzzle-loading cannon

• Coggins, Jack (1983). Arms and Equipment of the Civil War. New York, N.Y.: Fairfax Press. ISBN 0-517-402351.
• Cole, Phillip M. (2002). Civil War Artillery at Gettysburg. Cambridge, Mass.: Da Capo Press. ISBN 0-306-81145-6.
• Daniel, Larry J. (2015) [2005]. Cannoneers in Gray: The Field Artillery of the Army of Tennessee (Revised ed.). Tuscaloosa, Alabama: University of Alabama Press. ISBN 0-8173-5168-X.
• Eisenhower, John (1989). So Far From God: The U.S. War with Mexico 1846–1848. New York, N.Y.: Random House. ISBN 0-394-56051-5.
• Haecker, Charles M. (1994). "A Thunder of Cannon: Archaeology of the Mexican–American War Battlefield of Palo Alto". Santa Fe, N.M.: National Park Service.
• Hazlett, James C.; Olmstead, Edwin; Parks, M. Hume (2004). Field Artillery Weapons of the American Civil War. Urbana, Ill.: University of Illinois Press. ISBN 0-252-07210-3.
• Johnson, Curt; Anderson, Richard C. Jr. (1995). Artillery Hell: The Employment of Artillery at Antietam. College Station, Tex.: Texas A&M University Press. ISBN 0-89096-623-0.
• Katcher, Philip (2001). American Civil War Artillery 1861–1865. Osceola, Wisc.: Osprey Publishing. ISBN 1-84176-451-5.
• Ripley, Warren (1970). Artillery and Ammunition of the Civil War. Charleston, S.C.: Promontory Press. ISBN 0-88394-003-5.
• Shea, William L.; Hess, Earl J. (1992). Pea Ridge: Civil War Campaign in the West. Chapel Hill, N.C.: The University of North Carolina Press. ISBN 0-8078-4669-4.

• Downey, Brian (2019). "The Weapons of Antietam". Antietam on the Web.
• Morgan, James (2002). "Green Ones and Black Ones: The Most Common Field Pieces of the Civil War". civilwarhome.com.