The 1841 Mountain Howitzer, thought to be the type used in Rowlesburg during the Civil War
A howitzer (as illustrated above by Peter W. Gaut) is a short-barreled, large-caliber cannon designed to throw shells at a higher trajectory than regular field guns. This makes them useful against enemy troops behind fortifications or concealed in rugged terrain. The mountain howitzer was a special gun, designed on such a small scale that the entire piece could be taken apart and carried on pack animals. Although its 4.62-inch bore could handle the same 12-pounder ammunition as regular 12-pounder gun, a complete mountain howitzer, including the carriage, wheels and barrel, weighed less than the barrel alone of a larger 12-pounder field gun.
Mountain howitzers generally fired spherical case shot, canister or grapeshot. All of these types of ammunition, which scattered small shot and shell fragments, were effective within the shortened range of the mountain howitzer. Case shot for mountain howitzers carried a load of 82 lead musket balls. The shell was exploded above enemy positions by a fuse. Case shot was usually fired at enemy positions several hundred yards away. Canister consisted of tin-plated iron cylinders loaded with round shot packed in sawdust. Most Civil War canister contained iron shot, but canister rounds for the mountain howitzer were crammed with a load of 148 .69-caliber lead musket balls. Fuses were not needed for canister. A round of canister burst when the cannon was fired, blasting its load of musket balls out of the muzzle as if fired from a tremendous sawed-off shotgun. Canister was used from distances of about 400 yards to point-blank range. The load of lead from a round of canister made a little mountain howitzer as deadly as any other cannon at close range.
Because mules were nearly always used to carry mountain howitzers by packsaddle, companies with these little guns were sometimes called "jackass batteries." If the terrain permitted, the mountain howitzer could be mounted on its carriage and drawn by means of a pair of shafts by one of the mules. A few units did away with the packsaddles altogether and used a pair of horses to draw the gun.
This article was excerpted from: Norris, David A. "Confederate Gunners Affectionately Called Their Hard Working Little Mountain Howitzers 'Bull Pups'." (America's Civil War, September 1995), 10, 12, 14, 16, 20, & 90