4.5 Inch Rifle

Or perhaps we can call this post – the Heavy Iron of the Heavy Artillery!

Hunting down markers in Pennsylvania recently I came across this fine specimen of 4.5 inch Siege Rifle, Pattern of 1861:

4.5 Inch Ordnance Rifle at Millersburg, PA
4.5 Inch Ordnance Rifle at Millersburg, PA

Often, when one runs across the 4.5 inch Rifles, they are upright as monuments or gate guards.  So I took the time to examine this piece closely.  The muzzle displayed standard Ordnance Department markings for post 1861 regulations:

Muzzle Markings
Muzzle Markings

The business end indicates this piece was produced in 1863 by Fort Pitt Foundry, in Pittsburgh, PA.  It weighed 3556 pounds when inspected by Charles Peoble Kingsbury (initials C.P.K.).  And it was assigned the registry number 67.  Note the well worn rifling, which is badly deteriorated further into the bore.

A socket for the rear sight is just over the breech.  The tapped mounting holes for the front post are over the right trunnion.

Breech and Sight Socket
Breech and Sight Socket
Front Sight Mount Point
Front Sight Mount Point

At first glance, the 4.5 inch appears to be simply a “big brother” to the 3-inch Ordnance Rifle.  Think again.  This “heavy” does not use the wrought iron construction of the 3-inch type.  All 4.5 inch Rifles were produced by Fort Pitt Foundry, and used a rather conventional solid cast technique.  However, the external similarity between the two “Ordnance” rifle calibers is not coincidental.  Both used the form desired by the department, which reduced all sharp angles and stress points down to only those where the trunnions met the rimbases.  Even the knob is gracefully blended into the breech.

Some sources erroneously attribute the 4.5-inch (and even the 3-inch) Rifles to Thomas J. Rodman, better known for his work on heavy seacoast guns.  These rifles did not use the core-barrel water cooling technique during production.  Thus the attribution to Rodman does not make much sense, unless someone can prove Rodman developed the “Ordnance” shape itself.

Another point about the 4.5-inch construction, and perhaps the weakest point of the weapon, regards the vent hole at the breech (in the photo above it has been filled in).  The 4.5-inch Rifles used no vent bushing (also called bouching).  Under the stress of firing, the cast iron tended to erode badly at the vent.  Parrott Rifles and other types used a copper (or other metal) vent bushing, screwed down the vent hole.  Some 4.5-inch Rifles were retrofitted with such bushing.  Still the largest criticism of the type regarded the endurance of the vent.

Operationally, the 4.5-inch Rifle was rated a “Siege Gun” and saw wide use in the fortifications circling Washington.  However, Batteries B and M, 1st Connecticut Artillery were part of the siege train for the Army of the Potomac from late 1862 onward.  Photographic evidence indicates one of these batteries was in place opposite Fredericksburg in the winter of 1862-3.

4.5-inch Rifles at Fredericksburg

During the Gettysburg Campaign, the batteries were part of the 2nd Volunteer Brigade of the Artillery Reserve.   Battery M, 1st Connecticut was somewhere between Westminster and Taneytown, MD during the battle, and later joined the main army during the standoff at Jones’ Crossroads during the retreat.  Several batteries were used for good effect at Petersburg, of course. However since these “siege guns” were about three times the weight of a 12-pounder Napoleon and four times the weight of the 3-inch Rifles, their usefulness was limited for a field army.

The 4.5-inch Rifle matched up with the 30-pounder Parrott Rifle (4.2-inch caliber).  The Parrott, even with a slightly smaller caliber, weighed about 800 pounds more.  The maximum range of both types were similar.  At ten degrees elevation the 4.5-rifle ranged to 3200 yards with a Dyer shell.  At least one first hand account from the Connecticut batteries state the 4.5-inch Rifles were more mobile in action than the heavy Parrotts.

Of 113 produced, there are 56 identified survivors.  The example from my photographs is located in downtown Millersburg, PA, pointed out over the Susquehanna.

Published by Craig Swain

"Historical marker hunter" and Civil War enthusiast.

8 thoughts on “4.5 Inch Rifle

  1. So this begs a question—if the FPF 4.5-inch rifle was as reliable as and threw the same projectile weight as a 30-pounder Parrott but without a Parrott-type breech band, then was the breech band actually necessary? Strikes me that RPP could have saved the trouble and expense (to the government) and simply thickened up the breech as a one-piece casting. Thoughts?

  2. I live in Parkersburg WV and we have a 4.5 ” seige rifle that was brought here in 1898 and put on top of Fort Borman hill. It sat up there until 1921 when it was brought to our city park and put on a concrete platform where it sat for 100 years. The start of this year they removed it and had a carriage made for it and put back up on Fort Borman which is now a park. It really looks grand !! I can send you some pictures of it if you would like ??
    Greg Brown

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