Burst Iron: Failures of Tredegar 3-inch Rifles

Yesterday I closed mentioning this Tredegar 3-inch iron rifled field gun:

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3-inch Tredegar Gun at Gettysburg

The worn trunnions do not offer any markings, but the muzzle gives away the faint trace of “1464” and the number “962” appears near the vent.  While difficult to see in the limited light of the side exhibit in the new visitor center, those marks match to a 3-inch rifle cast by Tredegar on March 31, 1862.   The same gun appears on an itemized invoice posted on May 23 of that year.

Tredegar delivered the gun, mounted on a government carriage, on May 3.

On the same day, Tredegar delivered a similar rifled gun numbered 1462, along with a foundry made carriage and limber.  Both guns cost $195 – a five dollar increase over 3-inch rifles and 6-pdr smoothbores delivered a month earlier!

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Casting Seams

Like many Tredegar cannon from the 1862 time frame, #1464 exhibits casting seams indicating the lack of post-casting machine work.

As mentioned at the close of yesterday’s post, #1464 has a straight muzzle, matching the later 6-pdr smoothbore pattern.  If the foundry book is correct, Tredegar cast #1464 with a straight muzzle just a few days after #1450 (March 23) with a muzzle swell, and just two days before #1466 with a straight muzzle.  Again, these dates indicate either a very rapid switch in patterns, or short overlap in pattern use.

Tying #1464 back to the battlefield at Gettysburg, the sign beside the gun reminds visitors that Rowan’s North Carolina Artillery, led by Captain James Reilly, lost a similar 3-inch iron rifle on July 2, 1863.  The gun burst during the afternoon fighting.

Months earlier, failures put these and similar unbanded cast iron rifles into disfavor.  On November 13, 1862, Colonel Josiah Gorgas issued a circular limiting gun production to only bronze Napoleons and banded iron Parrott rifles (OR, Series I, Volume 21, Serial 31, page 1047).  This effectively ended the production 6-pdr smoothbore line and iron 3-inch rifles, although too late to prevent the failure of Reilly’s gun at Gettysburg. The bursting of that gun puts an underline and bold font on the lesson learned and re-learned in the long history of gunmaking.  Cast iron had to be carefully selected and handled in order to withstand the stress of firing.