Parrott Rifle

Origins

Robert Parker Parrott graduated from West Point in 1824 and served as an ordnance officer. In 1836 he resigned from the army to become superintendent of the West Point Foundry at Cold Spring, New York, on the Hudson River opposite the academy. In the late 1850s he began to experiment with rifled cannon. He produced his first rifled 10-pounder in 1860 and patented the design in 1861. Rifled guns threw a long, pointed shell farther and more accurately than a smoothbore could throw a round ball, but they put greater strain on the barrel. Parrott's answer was cheap and could be built quickly, which mattered when war came in 1861. The United States Army and Navy both ordered his guns in large numbers.

Design & Construction

A Parrott rifle was a cast-iron muzzle-loader with a thick band of wrought iron around the breech, where the pressure of firing was greatest. The band was made by coiling an iron bar, welding it into a hoop and fitting it hot onto the barrel. While it cooled and shrank, the barrel was turned and cooled with water from inside, so that the band gripped evenly. The plain tube and the heavy reinforce make a Parrott easy to recognize.

The guns were named by the weight of their shot. The field pieces were the 10-pounder, with a bore of 2.9 inches (changed to 3 inches in 1863), and the 20-pounder of 3.67 inches. The siege and naval guns were the 30-pounder of 4.2 inches, the 100-pounder of 6.4 inches, the 8-inch gun, often called the 200-pounder, and the 10-inch 300-pounder. They fired long shells and solid bolts with a soft metal ring or cup at the base that the powder gas forced out into the rifling. A 10-pounder could reach about 1,900 yards at five degrees of elevation and considerably farther at higher angles.

The weakness of the design was the cast iron. It was brittle, and Parrotts sometimes burst, usually ahead of the band and often without warning. The largest calibers had the worst record. Many field gunners preferred the wrought-iron 3-inch Ordnance Rifle.

Combat Use

Parrott rifles were in action from the first battles of 1861, and 10-pounder and 20-pounder batteries served in both armies for the rest of the American Civil War. They fought beside the smoothbore Napoleon 12-Pounder in most of the large battles, among them the Battle of Gettysburg. Confederate foundries, notably the Tredegar works in Richmond, made their own copies.

The heavy guns changed siege warfare. In April 1862 Union rifled guns under Quincy A. Gillmore, Parrotts among them, breached the brick walls of Fort Pulaski in Georgia from about a mile away. In July 1863 Gillmore brought Parrotts to Morris Island outside Charleston. Field and siege pieces joined the mortars and the fleet in the bombardment before the Second Battle of Fort Wagner, but the fort's sand walls absorbed the shells. After the assault failed, Gillmore turned his heaviest Parrotts on Fort Sumter. From 17 August they fired over Fort Wagner at ranges of two miles and more, and in about a week they battered much of Sumter's masonry into rubble. One 8-inch Parrott, the "Swamp Angel", was mounted in the marsh and shelled the city of Charleston from 22 August at a range of about four and a half miles. It burst on its thirty-sixth round. Many of Gillmore's heavy Parrotts burst during the campaign. The same happened at sea: several burst on Union warships during the first attack on Fort Fisher in December 1864, killing and wounding their own crews.

Legacy

The Parrott showed that rifled artillery could destroy masonry forts from beyond the reach of their guns, and brick and stone fortification went out of use within a generation. It also showed the limits of cast iron. After the war, armies turned to steel breech-loading guns, and the Parrott was retired. Parrott himself gave up the foundry in 1867 and died in 1877. Many of the guns survive in battlefield parks, where the banded breech makes them easy to pick out. Other heavy ordnance of the period includes the Siege Mortar.