An Oddity for Leesburg: Tredegar Rifle Siege Howitzer

When the Civil War broke out, rifled artillery was all the rage.  Officials took old guns in hand for conversion, usually amounting to cutting rifling grooves and adding a reinforce band.  At the same time the foundries took existing patterns and bored new guns out as rifles.  Some of these turned out well.  Others not so.  The better of these conversions were James or early Brooke rifles.  The worst of these conversions are best described as “oddities.”  In February 1862, one of those oddities arrived in Leesburg, Virginia.

To start out, in the summer of 1861, the Confederate Army ordered fifty 8-inch siege howitzers from Tredegar Iron Works.  Before the war Tredegar cast seven 8-inch Siege Howitzers Model 1841 for the US Government.  Those weapons weighed around 2,630 pounds.   The howitzers Tredegar sold to the Confederate government weighed about fifty pounds more, but are within the range for the 8-inch 1841 pattern.  Invoices show that Tredegar delivered only twenty-four of these smoothbore howitzers.  Two trophy howitzers captured outside Charleston, South Carolina, which have no foundry marks, may be the only survivors of Tredegar’s Confederate production (but such identification is based only on circumstantial evidence).

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8-inch Siege Howitzer at Washington Navy Yard

Included in the tally of twenty-four, Tredegar bored out four of these 8-inch howitzers as 4.62-inch rifles.  No documentation supports such design change.  Perhaps someone in the new Confederate ordnance department asked for rifled howitzers.  Perhaps Tredegar just rode the fad, trying to rifle everything.  Perhaps some state (Virginia) authority called for the rifles.  Or perhaps someone in the field had a specific tactical role for these weapons.

Regardless of the origin of the idea, all four examples saw at least brief service in Confederate defenses.  Tredegar sent the first two, foundry numbers 1279 and 1280, to Essex County, Virginia in December 1861, presumably for Rappahannock River defenses.  Invoices link that shipment to Robert M.T. Hunter, the Confederate Secretary of War, who hailed from that county.   The third howitzer, foundry number 1342, went to the Richmond defenses at Meadow Bridges Road.  All three of these pieces returned to Tredegar within months and were rebored as 8-inch smoothbores.  Given the time frame, likely these weapons recycled out to the Richmond defenses in the summer of 1862.

That leaves the fourth rifle howitzer.  An invoice from Tredegar, dated February 11, 1862, indicates that howitzer and a rifle siege gun also of 4.62-inch caliber went to General Daniel Harvey Hill in Leesburg.

According to the invoice, the 4.62-inch rifle howitzer weighed 3,390 pounds.  The weight increase is within the range expected given the increased metal used by reducing the bore by about a third.  Other lines in the invoice include Tredegar’s fee for handling the gun for shipping, and even the cost of proofing the gun.  (I wonder if Tredegar worked in a charge for the paper the invoice was written upon!)

On the right margin is a note, “Sent to Genl. D.H. Hill as per R.R. Receipt.”  That receipt was attached to the invoice.

The invoice and receipt leave not doubt this weapon was a rifle siege howitzer.  Using the receipt as the lead, this howitzer took the round about route from Richmond to Gordonsville on the Virginia Central Railroad.  From there it must have taken the Orange & Alexandria Railroad to the north.  Perhaps unloaded at Manassas, the howitzer moved overland to Leesburg for delivery.  With little doubt, the rifle howitzer went into one of the forts, possible Fort Evans, then around Leesburg.

So was this rifle howitzer any good?  Well consider the projectile weight, likely powder charge, and the piece itself.  The 4.62 bore matches the smoothbore 12-pdr size.  As such the elongated rifled projectile would weigh between 20 and 30 pounds.  Recall that a smoothbore 8-inch shell weighed around 42 pounds.  The bore size matched the 8-inch howitzer’s chamber size.  That places the powder charge around four pounds.  As noted above the howitzer itself weighed just over a ton-and-a-half.  The reduced windage and increased resistance with rifling probably presented some recoil issues when firing this piece.  But the nothing that could not be allowed for.

The real problems would be range and accuracy, given the weapon’s howitzer form.  The 4.62-inch rifle siege gun shipped to Leesburg on the same invoice was a modified 24-pdr siege gun.  The gun, with an indicated weight of 5,150 pounds, likely possessed performance figures similar to Federal 24-pdr guns altered to the James system.  So assuming all things equal, the Tredegar siege rifles might boast 1900 yard ranges on typical siege carriages.  At the same elevation, I would expect the rifled howitzer to only reach 1200 yards.

The howitzer’s small size would allow higher elevations, perhaps extending range out to 2000 yards.  There the question becomes one of accuracy.  With a shorter bore than the rifle gun, the howitzer’s velocity would be lower.  Accuracy then would suffer.  Perhaps after a few test fires, the gunners figured out the 3,390 pound howitzer was more an albatross to be handled about than a functional weapon.

As indicated above, the other three rifle howitzers went back to the foundry and were remade as smoothbores.  There is no record of the Leesburg howitzer undergoing such modification.  While the odds are that fourth howitzer underwent a similar transformation, with no paper record there is another possibility.  With the withdrawal from Leesburg in March, just weeks after the howitzer and gun were received, General Hill marched his men and equipment south.  The Confederates destroyed most of what they left behind. What if the Confederates likewise discarded the “junk” howitzer instead of hauling it south?  Perhaps that rifle howitzer remains here in Loudoun, waiting to be unearthed.  Stranger “oddities” have occurred.