30-pdr (4.2-inch) Army Parrott Rifle

I mentioned the 30-pdr Parrott Rifles during the previous post on Fort Pulaski.   Five of these guns pounded the fort from Battery Sigel.  Throughout the Civil War, the type served well in siege and garrison roles, accompanied field armies, and even served the Navy afloat.  A versatile gun to say the least.

Appomattox 18 Apr 10 254
30-pdr Parrott, Reg. 392, Appomattox C.H., Va.

The story of the 30-pdr starts before the war with the development of Robert P. Parrott’s system for rifled guns.  As related in previous articles, the 10-pdr was developed first (and the 20-pdr actually followed the 30-pdr).  While the 10-pdr, with the 2.9-inch bore, were sufficient for field duty, the Army needed larger calibers for siege and garrison roles.   Parrott chose the standard 9-pdr sized bore, then a dormant caliber in the Army’s system, with a 4.2-inch diameter.

Fort Pulaski 5 May 10 276
Breech Band of Reg. No. 333, Fort Pulaski, Ga.

The 30-pdr’s featured a 19-inch band over the breech.   The band added 550 pounds to the cannon’s weight.  The gun tube itself was 131.5 inches long, with a 120 inch deep bore.  Scaling up from the 10-pdr, the 30-pdr utilized five groove rifling, 1.3-inches wide.  As with all genuine Parrotts, the rifling was right-hand gain twist, increasing in pitch closer to the muzzle.  Overall the 30-pdr rifle weighed 4,200 pounds.

Fort Pulaski 5 May 10 273
30-pdr Bore - Reg 333, Fort Pulaski, Ga.

The 30-pdr used a modified 18-pdr siege gun carriage.  The Parrott’s trunnions were 5.3 inches in diameter, 4.75 inches long.  Distance between the rimbases was 16.8 inches.   This matched corresponding dimensions of standard 18-pdr siege guns.  However the Parrott was two inches longer from trunnion to breech face, necessitating modifications to the placement of the elevating screw.

At a pace which indicates bureaucracy was sidestepped, the Army rushed the larger Parrott into service.   The War Department ordered the first six 30-pdrs from West Point Foundry, New York in April 1861.  In an odd arrangement, Parrott, who designed the rifle and supervised the production, also inspected and accepted the weapons on behalf of the Army in June 1861.   The following month one of that first batch, in a crew directed by Lieutenant Peter Hains, fired the first shot of First Manassas.   The Federals were unable to get “Long Tom,” as it came to be called, off the field and the Confederates took possession.  The Confederate ordnance manual of 1862 provided ample detail of the piece, listing the weight as 4,190 pounds.   (Secondary references listed below match that weight to West Point registry number 2, which has unfortunately been lost to history.)

By the time West Point Foundry produced the last 30-pdr in April 1866, the Army had accepted 391.  Roughly half have survived the years as reminders of the war.  A survey of these indicates at least four pattern variations.  (West Point Foundry produced six additional 4.2-inch or 30-pdr Parrotts in 1864-5 to a modified pattern.  Based on trunnion dimensions and weight, these were probably used for comparison trials against the 4.5-inch siege rifles.  As such I don’t consider them “standard” Army 30-pdr Parrott rifles.)

All of the 30-pdrs with registry numbers below 52 feature a muzzle swell and “shoulder” in front of the trunnions, somewhat like the early production 2.9-inch Parrotts.  One of these is on display at Fort McAllister, Georgia.

Ft McAllister 5 May 10 101
30-pdr Parrott, Reg. 52, Fort McAllister, Ga.

The other notable feature of the early production 30-pdrs is the knob.  The photo below is the breech of an early production 30-pdr, whose markings have been lost to corrosion.

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Breech and Knob of early Production Parrott, Fort Pulaski, Ga.

Compare the early production knob with the later production knob on registry number 333 (above, second photo from top).  Early production featured a simple flattened knob.  Later production had a more robust knob with a hole or “piercing” of the knob.  This hole facilitated the use of navy style elevation screw fixtures.

While we are looking at the breech, notice the location of the elevating screw on the reproduction siege carriage.  Granted, reproduction tolerances are somewhat forgiving.  Still the screw head is very close to the base of the breech.  At high elevations, the breech might slip off the head and damage the screw.  The issue was a common complaint of the 30-pdr.

The early production 30-pdr pictured above also has faired rimbases.  Only two examples of such are known, and may indicate a simple casting variation.

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Faired Rimbase on Early Production Parrott, Fort Pulaski, Ga.

All other 30-pdrs, both early and late production, featured cylindrical rimbases.

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Cylindrical Rimbases, Reg. No. 333, Fort Pulaski, Ga.

This view also shows the gentle curve of the shoulder and lack of muzzle swell on late production 30-pdrs.  The lowest registry number with these features known today is 88, which was produced in 1862.

Another variation sometimes reported is the presence of breeching clevis as used on some Navy 20-pdrs.  I’ve not run across any of these in the field.  This sounds like the logical modification for Army contract 30-pdrs issued to the Navy while that service waited for Parrotts cast specifically for shipboard use.

None of these variations significantly impacted the performance or handling of the rifled guns in action.   The 30-pdr was credited with phenomenal (for its day) ranges during operations around Charleston, South Carolina in particular.  In his report of operations on Morris Island, General Quincy Gilmore noted the ranges for the 30-pdr firing 29 pound shells as 4,800 yards at 15 degrees, and 6,700 yards at 25 degrees.   For hollow shot, the range was 7,180 yards at 25 degrees and 8,453 yards at 35 degrees!  (Gilmore, Engineer and Artillery Operations Against the Defenses of Charleston Harbor, p. 83.)

Although the “Swamp Angle” got all the headlines, Gilmore mentioned a 30-pdr which more than matched it’s 8-inch (200-pdr) cousin.  A 30-pdr recorded as registry number 193, placed on Cumming’s Point fired shells into Charleston starting in December 1863.  Over sixty-nine days, the rifle fired 4,606 rounds.  Some were fired at 40 and even 50 degrees of elevation.  The range from Cumming’s Point batteries to Charleston was well over 6,500 yards.  Gilmore did not provide a reason for the failure, but the gun finally burst into several pieces (Gilmore, pp. 85-87).  Fragments of this remarkable gun are in the West Point collection today.  Still the failure underscores one of the main complaints about the Parrotts in general – the tendency to burst.

The big 30-pdrs served the Army through the Civil War, and into the last decade of the 19th century.  Along with the 4.5-inch siege rifle, the 30-pdr Parrott was considered the heaviest weapon that could follow the field armies on campaign.  And with a far more useful payload than its 20-pdr cousin, the 30-pdr was highly regarded for siege operations.  From firing the first shots of great battles to reducing fortifications at great ranges, the 30-pdr Parrotts more than proved themselves during the war.


Aside from on site notes and links provided above, sources consulted for this post were:

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.

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