The 6.4-Inch “Columbiad Rifle” of Fort Powell in Mobile

Aug 3

A 6.4-Inch Rifle which in all respects besides its rifled bore resembles a 10-Inch Confederate Columbiad may be found in downtown Mobile, Alabama.

A 6.4-Inch Rifle which in all respects besides its smaller, rifled bore resembles a 10-Inch Confederate Columbiad may be found in downtown Mobile, Alabama. The cannon was salvaged from the site of Fort Powell which guarded the Mississippi Sound entrance to Mobile Bay.

Warren Ripley’s Artillery and Ammunition of the Civil War records that this cannon is marked (pg. 84):

Muzzle Face: 1285 (Tredegar Foundry Number)
Right Trunnion: J.R.A. & Co., T.F. (Joseph Reid Anderson & Co., Tredegar Foundry)
Left Trunnion: 1861 (though Ripley noted that this number had been “noted at the time of salvage but obliterated during moving)
Tube: CSA
Cascabel, Top: 14850 (weight in pounds)

Ripley had the advantage of making his recordings six decades ago -before a fair number of coats of paint and additional weathering. I’m afraid I observed little of the markings he did. The records for Tredegar indicate that Number 1285 was cast as a “10-Inch”.

Externally, except for the bore, the cannon resembles a standard 10-Inch Confederate Columbiad. As Confederate Columbiads were cast solid and then placed on a boring machine to give them their correct bore diameter, the creation of this rifle simply involved boring the solid block to a 6.4-inch bore and then rifling that smaller bore.

However, this experiment in rifled cannon production was not a success. Ripley stated that these Columbiad Rifles (a 5.82-Inch was also produced from 8-Inch blocks) were not successful and were prone to bursting (pg. 83). In any event, it created a rifled cannon which was significantly heavier than other 6.4-Inch Rifles. The Brooke Rifle of this caliber, for instance, weighs about 10,000 pounds. Many 6.4-Inch Rifles were created by rifling and banding existing pre-war 32-Pounders. Taking a 10-Inch Columbiad block and creating an exceptionally heavy, unreliable rifle was quickly found to be an unwise proposition. This was especially true since regular 10-Inch Confederate Columbiads were one of the most effective cannons available to the South and remained in high demand throughout the war.

Olmstead et al. records that only two of these 6.4-Inch rifles were produced along with eight of the 5.82-Inch variety.

This cannon is, however, the earliest surviving Confederate 10-Inch Columbiad casting. It testifies that at least by October 1861 (the date of its casting) Tredegar was producing Columbiads using the new pattern which was modeled after the US Army Rodman design. (Though it was not produced according to Rodman’s hollow casting method.)

An 1865 photo shows what appears to be the breech of a banded Confederate Columbiad at a battery on the James River. Ripley speculated that it might be the other 6.4-Inch Rifle which was banded to cope with the unreliability of the type (pg. 64). If this had been done, however, it would have created a yet heavier piece - likely totaling near 16,000 pounds!