Bigger guns for Beauregard’s modifications: 10-inch banded and rifled Columbiads

In the summer of 1863, a set of modified 8-inch columbiads debuted in defense of Charleston.  J.M. Eason & Brother, in Charleston, banded these cannons and added 8-groove rifling (see the view of the muzzle in yesterday’s post).  But 8-inch rifles were not enough to deal with the Federal ironclads.  General P.G.T. Beauregard looked around for heavier smoothbores which might also undergo modification into rifles.  But at the same time, the Confederate Ordnance Department feared such modifications might prove useless, and damage otherwise perfectly fine weapons.

To circumvent objections, Beauregard’s ordnance officers identified a damaged cannon among those at Fort Sumter.  Sometime during the August bombardment, a 10-inch Model 1844 Columbiad suffered damage to a trunnion, making it a perfect candidate.  But the machinist making the change had to not only band and rifle the columbiad, but also replace the trunnion.  The columbiad selected is among Fort Moultrie’s set of cannons today:

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10-inch Rifled and Banded Columbiad

The columbiad was originally registry number 7 from Cyrus Alger, of Boston, Massachusetts.  John Wolfe Ripley inspected the columbiad in 1846, as evidenced by his initials on the muzzle, opposite the registry number:

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Muzzle of 10-inch rifled columbiad

This particular columbiad was among those used for metal sampling experiments prior to the war.  The divot at the 8 o’clock position is from those tests.  The other scar, at the 11 o’clock, may be battle damage from the war.

Eason was up to the challenge for this complicated conversion.  The workers started by turning off both trunnions along with the original base ring on the back of the gun.  While on the lathe, the workers also gave the gun a slight taper back towards the breech.  At that point, the columbiad likely received its rifling – fifteen grooves, right-hand twist.

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Rifling, and debris…

Thus prepared, Eason’s foundrymen made a wrought iron band that would slip onto that tapered breech.   Then the workers put a second iron band to provide even more reinforce to the breech.  Then they slipped a bronze trunnion band, fitting snugly on top of the inner band and butting against the front of the outer band.

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Bands on the 10-inch rifled columbiad

To secure the trunnion band, which might let the gun slip during firing, Eason put a plate over the breech.  Four rods ran through that plate and the trunnion band.  Threading on the forward end of the rods indicates threading through the bronze.  To the breech end, the rods have hexagonal heads.

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Breech face of 10-inch rifled columbiad

From the breech face, the inner band layer is visible, along with the plate holding the trunnion band in place.  Note also the original weight stamp – “15210” – and Eason’s “J.M.E. & Bro.” stamp on the inner band.  Beauregard indicated the columbiad weighed 22,000 pounds as modified.

Other marks stamped on the gun included a “C.S.” on the trunnion band:

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Trunnion band stamp – “C.S.”

On the left trunnion, Eason put their stamp along with the year of modification:

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Left trunnion of 10-inch rifled columbiad

After Eason completed the modifications turning what was a smoothbore into a rifle, the columbiad went to Sullivan’s Island early in December, 1863.  There it became part of Battery Bee.  A couple of photographs taken at the end of the war show it was still at that location.  I don’t have access to a digital copy of either photograph, but one was used in the old marker behind the gun:

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Marker for columbiad

I say “old marker” as this gun was part of the cannon-row preservation project and should by now have updated interpretation.  But you can easily make out the rods over the top of the bands.  Almost looks like a recoil mechanism!

According to Federal engineering diagrams produced after the fall of Charleston, the 10-inch rifled columbiad was on the far right end of Battery Bee (yellow shaded section).


The Federals even provided profiles for that position.


This being a new weapon, the Confederates gave the columbiad a trial on January 16, 1863.  Two days later, Brigadier-General Roswell Ripley reported the results to headquarters in Charleston:

I have the honor to report that the double-banded and rifled 10-inch gun was fired on the 16th instant, from Battery Bee, with the following results:


The condition of the gun, carriage, and chassis is apparently as good as before it was fired.  The projectiles took the grooves in every instance, and the line of fire before ricochet was accurate. The ranges were estimated from Mount Pleasant.  The difference I attribute to errors in taking elevations with plummet quadrant, to unequal weights, and, in some instances, unequal lengths of the shot, which should be avoided for the future.  The projectiles were all flat-headed bolts, which, of course, would not permit so good a range as with the pointed.  The time of flight could not be determined for want of a stop-watch, but the velocity appeared to be fully equal to that of the round ball.  The experiments I conceived to be sufficient to demonstrate the efficiency of the gun in its present position.

So Beauregard’s chance paid off with a rather useful weapon.  An 1,800 yard range was comparable to smoothbore 10-inch columbiads firing a lighter, solid shot at similar elevation.  The rifled columbiad could cover the entrance to Charleston harbor with ease.

Success prompted one more modification.  The subject was again a 10-inch Model 1844 Columbiad.  But this one required less work, as the trunnions were intact.  It’s wartime station was Fort Johnson.

That columbiad also exists today and is on display at Fort Sumter.  But I’ll save it’s story for now.

Witnesses to the opening shots of the Civil War, the ironclad attack of April 7, 1863, the destructive bombardment of Fort Sumter in August 1863, and several other engagements…

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10-inch rifled columbiad on Cannon Row, Fort Moultrie

… both remained around Charleston after the war was over.  Today they are unique artifacts with stories to tell.

(Citation from OR, Series I, Volume 28, Part II, Serial 47, pages 565.)

Published by Craig Swain

"Historical marker hunter" and Civil War enthusiast.

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