Earlier I discussed the particulars of the 6.4-inch Parrott Rifles. Now I turn to the functional aspects of the type, taking a look at the projectiles and mountings used.
The 6.4-inch rifles usually fired bolt (solid shot) and shell projectiles, with case shot as an option. But even within the short list of options, an array of variations existed. West Point Foundry, where the guns were made and Robert Parrott was superintendent, also produced many projectiles for the weapon. Parrott produced bolts with both flat noses and a “bottle top” nose. The later type featured a “chilled” iron or steel core surrounded by a cast iron body. The Navy preferred the “bottle top” for better penetration against armored plate. However, both services shared stocks of projectiles during the war. West Point also produced a “hollow” shot, where the reduced weight translated to higher initial velocities. Parrott provided “long” and “short” varieties of shells. Furthermore a specialized incendiary shell replaced traditional explosives with a chemical mixture.
Parrott was not the sole source for 6.4-inch munitions. Fuze and projectile inventor Andrew Hotchkiss also supplied bolts and shells for the 6.4-inch Parrott rifles. John P. Schenkl also provided bolts and shells, along with case shot projectiles. Confederates did produce some projectiles, mostly copies of the standard flat nosed Parrott type. In addition, both the Navy and Army tested experimental projectiles for the 6.4-inch with an aim to increasing armor penetration.
Perhaps just an expedient option, the Navy’s Ordnance Instructions of 1866 indicated that round shot from 32-pdr smoothbores could be fired from the 6.4-inch Parrotts. Instructions called for a canvas bag to cover the round shot. When fired standard smoothbore charges, the shot was effective “particularly on ricochet.”
Field reports complained about the projectiles in this caliber. Often the brass sabot of the Parrott rounds failed to expand when fired. As a partial remedy, both Navy and Army officers directed crews to separate the sabot from the bolt or shell with a chisel before firing. The lead sabots of the Hotchkiss rounds often separated from the projectile – attributed by some to the increased-gain rifling of the Parrott guns. While the Schenkl round received praise, after the death of the inventor in 1863, quality of the papier-mâché sabots dropped off.
The Army intended to use the 6.4-inch guns in the seacoast defense and siege roles. Wartime photos show the use of two types of iron carriages. An often reproduced view shows a “100-pdr Parrott” at Fort Totten in the Washington Defenses on a center pintle barbette carriage.
This carriage worked well on the parapet of seacoast fortifications and in inland defenses (as seen here). For the lower tier batteries within masonry forts or on offensive siege lines, the Army used a front pintle barbette. An example is seen here in use in the Petersburg siege lines.
The Navy used Parrotts of this caliber mostly on pivot mounts. However, broadside Marsilly carriages are also mentioned in the instructions.
Both Navy and Army instructions called for a 10 pound powder charge. In a post war revision of the Manual of Heavy Artillery, John C. Tidball offered this range chart for the 6.4-inch Parrott firing a 100 pound shell with a 10 pound powder charge:
A maximum range of 3100 yards at 9 degrees elevation. For the days of muzzle-loaders and black powder, the 6.4-inch performed well. Note the range table does not cite ranges at higher elevations. Wartime reports indicate the guns could reach out over 8000 yards.
In my next look at the 6.4-inch Parrott rifles, I will look at the operational use of the big guns.
Aside from links provided above, sources consulted for this post were:
Bell, Jack. Civil War Heavy Explosive Ordnance: A Guide to Large Artillery, Projectiles, Torpedoes, and Mines. Denton, Texas: University of North Texas Press, 2003.
Olmstead, Edwin, Wayne E. Stark, and Spencer C. Tucker. The Big Guns: Civil War Siege, Seacoast and Naval Cannon. Alexandria Bay, NY: Museum Restoration Service, 1997.
Ripley, Warren. Artillery and Ammunition of the Civil War, 4th Edition. Charleston, S.C.: The Battery Press, 1984.
Tucker, Spencer. Arming the Fleet: U.S. Navy Ordnance in the Muzzle-Loading Era. Annapolis, Maryland: Naval Institute Press, 1989.