Table of Contents 6-pounder Field Guns 12-pounder Field Guns (including Napoleons) Siege Guns Seacoast Guns 32- and 42-pounders Rodmans and Confederate Columbiads
6-pounder Field Guns
The 6-pounder field gun was a lightweight, mobile piece that was a
favorite of the field artillery in the first half of the nineteenth
century. Rapid changes in technology and design had largely superseded
it by the beginning of the American Civil War, but when superior
weaponry was not available, some 6-pounders saw action. NOTE: While
some of the guns illustrated here may have played little or no part in
the Civil War, they are included here because photos of them can be difficult to find.
6-pounder iron field gun, Model of 1819. Total length, 71.6
inches; weight, 742 pounds; total production, approximately 100 by Fort
Pitt Foundry; known survivors, 30. Known as a "Walking Stick" for its
slimness, this is the first identified model with full rimbases. It
pioneered simplicity of design that was not to be fully accepted for
another forty years. Its 10-inch diameter reinforce, combined with the
unreliable cast iron of that period, proved notoriously fragile.
6-pounder iron field gun, Pattern of 1827. Total length, 57
inches; weight, 780 pounds; total production, 98 by Fort Pitt Foundry;
known survivors, 7. A stubbier version of the Model of 1819.
6-pounder iron field gun, Model of 1834. Total length, 60.5
inches; weight, 835 pounds; total production, 134 by Columbia and Fort
Pitt Foundries; known survivors, 16. The guns of this pattern were the
last fieldpieces made by either foundry.
6-pounder bronze field gun, Model of 1835. Total length, 65.6
inches; weight, 740 pounds; total production, 57 by Cyrus Alger and
N.P. Ames; known survivors, 19. This slimmer version of the later Model
of 1841 represents the return to bronze as the preferred material for
6-pounder iron field gun, Model of 1836. Total length, 65.6
inches; weight, 785 pounds; total production, 13 by Alger; known
survivors, 3. Identical in design to the bronze Model of 1835 above.
6-pounder bronze field gun, Model of 1838. Total length, 59.3
inches; weight, 690 pounds; total production, 96 by Cyrus Alger and
N.P. Ames; known survivors, 29. A shorter version of the bronze Model
of 1835 above with the same Registry Number series continuing from it
for both foundries.
Markings on bronze Models of 1835 and 1838 fieldpieces. Unlike
the markings on earlier and later cannon, the Registry Number, weight
and inspectors' initials are located on the upper breech.
6-pounder bronze field gun, Model of 1840. Total length, 59.3
inches; weight, 812 pounds; total production, 27 by N.P. Ames; known
survivors, 4. A slightly thicker version of the bronze Model of 1838
above with the Registry Number series continuing from it.
6-pounder bronze field gun, Model of 1841. Total length, 65.6
inches; weight, 880 pounds; total production, 817 for U.S. Army
Ordnance by Alger (197), Ames (540), Hooper (8), Marshall (23), and
Revere (2) plus perhaps 50 more for various state agencies; known
survivors, 325. Many of these guns were reamed and rifled to 3.80-inch
James rifles, Type 1, at the beginning of the Civil War.
6-pounder bronze cadet gun by Cyrus Alger. Total length, 50.5
inches; weight, 570 pounds. Four of these guns were produced for
Virginia Military Institute in 1848, two for Arkansas Military
Institute in 1851, and four for Georgia Military Institute in 1852. Of
these ten, seven are known to survive. These guns were intended only
for drill and instruction; however, a shortage of fieldpieces in the
Confederacy at the beginning of the Civil War resulted in their being
commandeered for active duty.
6-pounder bronze James gun. Total length, 74 inches; weight,
860 pounds; Ames Co. cast six of these guns for U.S. Army Ordnance in
late 1861. All survive at Shiloh National Military Park. An unknown
quantity, of which four are known to survive, was later made for State
of Connecticut (survivors are dated 1862 and 1864).
6-pounder iron Stedman field gun. Total length, 69.5 inches;
weight unknown. An unknown quantity of these guns was made in 1861 by
Stedman & Co. of Aurora IN, of which two survive. Little is known
of their wartime service, if any.
Historical research information kindly provided by Jim Bender, the keeper of the "National Registry of Known Surviving Civil War Artillery," revealed a
newspaper article from the period indicating that the Stedman Foundry had been
awarded a contract from the State of Indiana to produce 12 cannon (one
for each of the counties bordering the Ohio River).
No 1 & No 5 survive today. The weight of No 1 is 1492 lbs; No 5 is 1480 lbs.
6-pounder wrought-iron Griffen field gun, Type 2. Total length,
72 inches; weight, 1030 pounds; total production, perhaps 18 made of
wrought iron by Phoenix Iron Company for Commonwealth of Pennsylvania
in 1861; known survivors, 13. Little is known of their wartime service,
6-pounder Austrian bronze field gun. Total length, 61.5 inches;
weight, 730 pounds. Of at least seventeen of these guns purchased in
Europe for the Confederacy by Major Caleb Huse, six are known to
survive. Because their bore diameter is 3.74 inches, rather than the
3.67 of American 6-pounders, the Confederate Field manual of 1862
advised that standard ammunition was to be wrapped in canvas for
6-pounder Brennan (Confederate) iron field gun. Total length, 66 inches; weight, 890 pounds; total quantity, about 30; known survivors, 11.
6-pounder Clark (Confederate) bronze field gun. Total length,
65.5 inches; weights of 12 known survivors vary from 820 to 894 pounds.
The quantity of these guns cast is unknown but was probably about 50.
Some Clark guns are completely marked and often profusely engraved;
others have no markings but are easily identified by the bulbous muzzle
swell unique to cannon cast by John Clark of New Orleans.
6-pounder Ellis & Moore (Confederate) iron field gun. Total
length, 65.6 inches; weight, 1010 pounds; quantity made, unknown but
probably 6; known survivors, 2. One of these guns is known to have been
captured at Fort Zollicoffer. Ellis & Moore was located at
6-pounder Leach & Avery (Confederate) iron field gun. Total
length, 66 inches; weight, 766 pounds; quantity made, unknown but
small. This extremely well-finished gun is the only known surviving
cannon made by Leach & Avery of Tuscaloosa AL, probably in 1861.
6-pounder Noble (Confederate) bronze field gun. Total length,
72 inches; weights of eight known survivors vary from 835 to 920
pounds. Surviving records indicate that about 20 of these bronze guns
were cast by Noble Brothers of Rome GA. All eight surviving Noble
bronze guns were cast in 1862 and have a distinctive flattened knob
suggestive of a spool of thread.
6-pounder Noble (Confederate) iron field gun. Total length.
72.5; weight, 900 pounds; quantity made, unknown; known survivors, 5.
Survivors found both with and without muzzle swell. The same pattern
was used by Tredegar Foundry to cast at least 31, and possibly
40, nearly identical 6-pounder iron guns of which there are 10 known
survivors. The only difference between Noble and Tredegar guns of this
pattern is the faired rimbases on the latter. Note that this pattern is
similar to the Brennan 6-pounder iron guns that are 6.5 inches shorter.
The bulbous breech is the distinctive feature of these Confederate iron
6-pounder Noble (Confederate) iron field gun. Total length, 59
inches; weight, unknown; quantity made, unknown. Neither the single gun
nor the three surviving 3-inch rifles made with the same pattern bear
any markings other than post-war arsenal inventory numbers; however,
the knob shape almost certainly identifies them as Noble tubes.
6-pounder Paxton (Confederate) bronze field gun. Total length,
65 inches; weight, 860 pounds; total production, 14 from late 1861
through mid-1862. Known survivor, 1. A.M. Paxton of Vicksburg MS also
finished two bronze guns cast by Quinby & Robinson.
6-pounder Tredegar (Confederate) bronze field gun. Total length, 65.6 inches; weight, 860 pounds; total production, 34; known survivors, 11. Identical to Federal Model of 1841.
12-pounder Field Guns (including Napoleons)
12-pounder iron field gun, heavy, early unknown pattern.
Several guns of this and similar patterns survive, both with and
without rimbases. While almost certainly made prior to 1830, some would
have been available to both sides and utilized during the Civil War.
Total length, various to 85 inches; Weights vary to 1,800 pounds.
12-pounder iron field gun, heavy, experimental battery of 1834.
Total length, 73.3 inches; weight, 1,697 pounds; total production, 3;
known survivors, 2. These guns, along with three 12-pounder and three
24-pounder iron field howitzers, were cast as a mixed battery at
Columbia Foundry in 1834.
12-pounder bronze field gun, heavy, Model of 1835. Total
length, 85 inches; weight, 1,800 pounds; total production, 23 by Ames
and Alger; known survivors, 8. With the exception of its large (8-inch
diameter) rimbases, this model is essentially identical to the Model of
1841 below. Alger and West Point Foundry cast a few similar iron guns
in 1838 that were designated 12-pounder iron field gun, Model of 1836. There is one known survivor.
12-pounder bronze field gun, heavy, Model of 1841. Total
length, 85 inches; weight specified as 1,800 pounds, but survivors
average about 1,760 pounds. Total production, 63; known survivors, 30.
Some of these smoothbore guns were rifled with 18-grooves at the
beginning of the Civil War. Alger and Ames each made one as 4.62-inch
rifles with 12 grooves in 1861. Both survive. NOTE: Tredegar Foundry
produced at least eight of these guns as Confederate guns, five of
which are known to survive.
12-pounder bronze field gun, light, Model of 1857 (Napoleon), with handles.
28 or 29 Federal Napoleons were made with handles: Alger Registry
Nos.1-4, Ames Registry Nos.1-23 (and possibly No. 24), and Revere
Registry No.2 (cast before No.1). 23 of these 28 or 29 are known to
survive. This is the second pattern Federal Napoleon. Specifications,
except for handles, are identical to those noted below. The first
pattern consisted of only one specimen, Ames Registry No.1, which
survives at Petersburg National Battlefield. It is three inches shorter
than all subsequent Federal Napoleons.
12-pounder bronze field gun, light, Model of 1857 (Napoleon).
Total length, 72.55 inches; weight, 1,220 pounds; total production for
U.S. Ordnance Department, 1,130. Perhaps another 50 were sold by Ames,
Greenwood and Revere directly to states; known survivors, 672
(including those with handles noted above). This is the third and final
pattern of Federal Napoleons.
Federal Napoleon rimbase juncture. All Federal bronze Napoleons have cylindrical rimbases that join the barrel with a sharp corner.
Breech contour of Alger, Ames and Revere Napoleons.
Napoleons from these three foundries have a small pad at both the top
and bottom of the breech indicated by the arrows in the photo. The top
pad is termed a "hausse seat" for the attachment of a pendulum hausse
bracket and the bottom pad a "base plate" on which the elevating screw
rested. Napoleons from Henry N. Hooper were made with only the top pad
for the sight bracket. Greenwood Napoleons have neither pad. Survivors
from this foundry may have holes drilled in various locations on the
upper breech utilized for mounting rear sights or sight brackets.
Wrought-iron Napoleon by Phoenix Iron Co. Total length, 72
inches; weight, 1215 pounds. No record has been found for production of
this unique surviving specimen nor any indication of how many were
made. It is the only Federal Napoleon with faired rimbases and the only
Napoleon made of wrought iron.
Confederate bronze Napoleon, final pattern. Total length, 72
inches; weight, 1220 pounds with large variations; production,
approximately 350. Known survivors, 137. This is by far the most common
form of surviving Confederate Napoleon. Those made at Augusta
(approximately 100), Charleston (perhaps 10), Columbus (approximately
55) and Macon (approximately 60) Arsenals, and most made at Tredegar
Foundry (122), are of this general pattern. Knob shapes vary
considerably among Confederate Napoleons but generally resemble that
shown in this photo.
Confederate bronze Napoleon by Leeds & Co. Total length 72
inches; weight, unmarked but assumed to approximate 1220 pounds. Leeds
made approximately 20 Napoleons, all closely resembling but having a
smaller muzzle cavetto than the Union patterns. There are 13 known
survivors. A single survivor from Quinby & Robinson is also similar
to this pattern.
Confederate cast-iron Napoleon. Total length, 72 inches;
weight, 1250 pounds; known survivors, 9. Tredegar Foundry made 121 from
January 1861 through February 1865. The reinforcing band is presumed to
be of wrought iron.
Confederate Napoleon rimbase juncture. Confederate Napoleons
produced at Augusta Arsenal and by Leeds & Co. utilized cylindrical
rimbases that joined the barrel with a sharp corner as illustrated
above for Federal bronze Napoleons. All other Confederate Napoleons
utilized faired rimbases with the smooth barrel juncture illustrated
Napoleon firing demonstration at Petersburg National Battlefield
Robinson's Battery firing an M1841 bronze 6-pounder
Photo courtesy of Roger M. Thoreson
12-pounder iron siege gun, Model of 1840. Total length, 116
inches; weight, 3550 pounds; total production, 20; known survivor: 1.
This model differs from the Model of 1845 only in having a single
tapered reinforce 51 inches long.
12-pounder iron siege gun, Model of 1845. Total length, 116
inches; weight, 3583 pounds; total production, 43; known survivors, 10.
While difficult to see in the photo, this model has a cylindrical first
reinforce 17 inches long and a second tapered reinforce with a length
of 34 inches. All other features and dimensions are identical to the
Model of 1840.
12-pounder iron siege gun, Confederate. Pictured is one of two
identical guns surviving at Rock Island National Cemetery. While
apparently unmarked, these are almost certainly of Confederate
manufacture, perhaps made in Memphis, TN. Two others for which we have
no reproducible photo survive at Fort Donelson National Military Park,
TN. The limited readable markings indicate the latter were made in
18-pounder iron siege gun, Model of 1845. Total length, 123.25
inches; weight, 4902 pounds; total Federal production, 52; known
survivor, 1. A second known survivor of this model is Confederate, one
of six cast by Tredegar Foundry for State of Georgia and shipped to
Savannah in early March 1861. This model (pictured here) has a
cylindrical first reinforce 21 inches long and a second tapered
reinforce with a length of 32.65 inches. The similar 18-pounder iron siege gun, Model of 1840,
has a single tapered reinforce 53.65 inches long. All other features
and dimensions are identical to the Model of 1845. Weight, 4752 pounds;
production, 20; known survivor, 1.
24-pounder iron siege gun, Model of 1819. Total length, 123.95
inches; weight, specified as 5790 pounds but actual weights averaged
close to 5500 pounds; total production, 1,125; known survivors, 74.
Some of these in Confederate hands, including at least six of the known
survivors, were rifled during the Civil War.
24-pounder iron siege gun, Model of 1840. Total length,
124 inches; weight, 5750 pounds; Army Ordnance documents tally production
of only one gun of this model (in 1841). The only two known survivors
have the "U.S." marking and are dated 1844; so production, although
unknown, was higher than indicated by the records. This model has a
single tapered reinforce 54 inches long.
24-pounder iron siege gun, Model of 1845. Specifications
are the same as the Model of 1840 above. The only difference is that
the Model of 1845 has a cylindrical first reinforce 22 inches long and
a second tapered reinforce 32 inches long. In addition to total
production of 66 Model of 1845 guns by Alger, Tredegar and West
Point Foundries from 1845 to 1853, four 1851-dated survivors marked
for South Carolina indicate Tredegar also contracted directly with
individual states. Known survivors, 14.
Confederate 8-inch banded siege gun. Tredegar Foundry cast 19
of these guns during the latter part of 1863 and through July 1864.
Bellona Foundry also cast as many as 16, the last of which was finished
at Tredegar as late as 6 March 1865. Like Brooke rifles and smoothbore
guns, the chase is a simple truncated cone. While there is no known
surviving specimen or dimensioned drawing of this gun, Tredegar records
document the finished weight of those cast there averaged 5,862 pounds.
Seacoast Guns 32- and 42- Pounders
32-pounder seacoast gun of 62 hundredweight. Total length,
127.75 inches; weight, 7000 pounds; total production, unknown; known
survivors: 11. The survivors were among 19 issued for monuments from
Castle Williams during the fiscal year ending 30 June 1901. Little more
is known of them except that they are obviously of American
manufacture, probably circa War of 1812. They are distinctive in having
triple fixed front and rear sights, one centered and the other two
about 70 degrees left and right of center. Registry Numbers of
survivors range from 47 to 70, but they have no marking for foundry or
32-pounder seacoast gun, Model of 1829. Total length, 125.2
inches; weight, 7479 pounds; total production, 1,222; known survivors,
51. This model was produced from 1829 to 1839 by Bellona, Columbia,
Fort Pitt and West Point foundries. It has a single reinforce 57 inches
long and a breeching ring. Survivors evidence that several in
Confederate hands were rifled, but not always banded, during the Civil
32-pounder seacoast gun, Model of 1845. Total length, 125.7
inches; weight, 7250 pounds; total production, 182 by Alger, Fort Pitt,
Tredegar and West Point foundries; known survivors, 19 of which three
are rifled with nine right-hand grooves but not banded. There is no
known survivor or reproducible photo of the similar but slightly
slimmer 32-pounder seacoast gun, Model of 1840 of which a total
of 50 were made by Bellona, Columbia and West Point foundries from 1841
to 1843. Its average weight was 6,967 pounds due to first reinforce and
base ring diameters each 1 inch less that those of the Model of 1845.
The thickness of its breech and knob length were slightly less than the
Model of 1845, making its total length 125.2 inches. Both models are
identical forward of the end of the first reinforce.
42-pounder seacoast gun, Model of 1831. Total length, 129.4
inches; weight, 8687 pounds; total production, 167 by Bellona, Columbia
and West Point foundries from 1831 to 1840; known survivors, 8. Its
single 52.2-inch reinforce and breeching ring are distinctive features.
42-pounder seacoast gun, Model of 1839. Total length, 129.3
inches; weight, 8486 pounds. Total production, 14 by Bellona, Columbia
and West Point foundries from 1839-1841. The Models of 1839 siege and
seacoast guns, seacoast howitzers, and siege and seacoast mortars were
prototype patterns that were further refined to become the Models of
1840. Usually, only a single Model of 1839 tube of each type was cast
by two or three foundries. An exception to this quantity occurred with
the 42-pounder gun, Model of 1839. Bellona Foundry, through some error
or misunderstanding, produced and Army Ordnance accepted 12 Model of
1839 guns in 1841 against an order for Model of 1840 guns. The
42-pounder gun pictured here, West Point Foundry Registry No.1 at
nearly inaccessible Battery Bienvenue LA, is the only known surviving
Model of 1839 iron tube of any type.
42-pounder seacoast gun, Models of 1840 and 1845. Total
length, 129 inches; weight, 8500 pounds. While orders, inspections, and
deliveries are recorded as two separate model years with separate
series of Registry Numbers, there is no dimensional difference between
the two models. The only disparity is that Model of 1840 are
lathe-turned only at critical components (muzzle, breech, trunnions and
rimbases) while Model of 1845 are fully lathe-turned. Total production:
40 Model of 1840 by Columbia and West Point foundries from 1841 to
1845; 318 Model of 1845 by Alger, Bellona, Fort Pitt, Tredegar and West
Point foundries; known survivors, 3 Model of 1840, 29 Model of 1845.
More than half of the known survivors were rifled by both sides (some
also banded) during the Civil War.
42-pounder seacoast gun, Confederate, banded. Same
specifications as immediately above. Tredegar Foundry cast four of this
type for State of Georgia early in 1861 and four more for the
Confederacy later that same year. Bellona Foundry probably also made a
few. The only known survivor is that pictured here, Tredegar No.1217,
cast on 2 May 1861 and having a marked weight of 8445 pounds. Typical
of large Tredegar cannon, most of its surface is as-cast with only
critical areas lathe-turned. It was later banded by Eason Brothers (so
marked) of Charleston SC, but it is not rifled.
Rodmans & Confederate Columbiads
The 8-inch and 10-inch Confederate Columbiad guns are included on this page
because many people will expect to find them here. It is unfortunate
that these guns have been associated with Rodmans and are even
frequently referred to as "Confederate Rodmans." Both are large guns,
and both can be termed "Columbiads." Other than having a superficial
resemblance to Rodmans, Confederate Columbiads have very little else in
common with Rodmans. Some differences are:
Rodmans were cast using the Rodman process of internally
cooling a hollow core (now referred to as "wet chill"); Confederate
Columbiads were poured solid.
The Rodman profile is a sweeping continuous curve, in all
sizes, with not even a minute cylindrical portion at the reinforce. The
8-inch Confederate Columbiad has a 21.5-inch cylindrical reinforce; the
10-inch has a 19.0-inch cylindrical reinforce.
Rodmans have short trunnions for use with wrought-iron carriages. With
only two known exceptions, Confederate Columbiads have long trunnions
for use with wooden carriages.
The Rodman bore bottom is an extended hemispheroid; the bore bottom of the Confederate Columbiad is a hemisphere.
The Rodman is fully lathe-turned; the Confederate Columbiad is
lathe-turned only at the trunnions, retaining its mold marks and
Rodman's Great Guns
This article was written by Donald B. Webster and was first published in
Ordnance in the issue of July-August, 1962. It has been edited and
corrected by Wayne Stark.
Due to the skill of a young ordnance officer, a new type cannon was
developed that was more effective than any previously constructed. The
years of the Civil War, and the five years preceding it, are quite
rightly considered a period of ordnance and artillery experimentation,
development, and transition. The work of one man led to the casting of
some of the largest cannon ever built, even to the present day:
monstrous 20-inch muzzleloaders that fired 1,080-pound solid shot.
In 1844 Lieut. Thomas Jackson Rodman, a young ordnance officer
only three years out of West Point Military Academy, began a long
series of experiments aimed at overcoming the principal difficulty in
casting large iron cannon, a difficulty that effectively set a maximum
size limit for iron cannon. At that time cannon were cast solid and
were cooled only from the outside. This practice caused the cooling
metal to contract toward the outer surface of a cannon barrel and, in
large castings, created internal strains and structural irregularities
in the metal as well as "pipes" or "blowholes," actual cavities within
the casting. In short, large cannon all too often had a habit of
cracking in cooling, breaking in transport, or finally bursting when
fired. Over a period of years, Rodman devised a theory to account for
both internal strains and imperfections and for variations in the
density, hardness, and tensile strength of the metal in cast-iron
cannon. He developed and patented a process for casting cannon around
hollow cores and cooled from the inside, via a jacketed stream of
running water, rather than external cooling.
Rodman was confident his process would cause the cooling metal
to contract toward the bore and increase the density of the metal where
it was most needed. The bore would later be reamed out and polished,
eliminating any surface imperfections. The rate of cooling could be
controlled by regulating the temperature and rate of flow of the water.
By following his procedures, Rodman claimed he could cast cannon of any
bore size, 6.4 inches or larger. Working at Knap, Rudd & Company's
Fort Pitt Foundry at Pittsburgh, founded in 1804 and perhaps one of the
largest foundries in the world, Rodman conducted a series of
experiments and trials that lasted nearly ten years.
Experimental cannon were carefully cast in pairs, one on the
old solid core system, the other around variations of Rodman's hollow
core process. Of one pair, the gun cast on Rodman's principle was fired
1,500 times; its counterpart, cast on a solid core and cooled
externally, burst on the 299th shot. In another test of guns purposely
made of poor material, Rodman's internally cooled gun fired 250 times
and held together; the other piece burst on the 19th round. Completely
satisfied by Rodman's results, in 1859 the War Department authorized
the casting of a 15-inch smoothbore columbiad. This gun, cast in 1860
under Rodman's personal supervision at Fort Pitt Foundry, was sent to
Fortress Monroe, Va., where it was tested in March 1861 and became a
model for the many Rodman guns that followed. The new gun proved a
great success, although its huge size and weight, 49,099 pounds for the
barrel alone, made it practical only for fixed positions in forts or
permanent batteries. Specifications were impressive. The 15-inch Rodman
gun is 15 feet, 10 inches long with a bore length of 13 feet, 9 inches,
or 11 times caliber, a good deal shorter than the general rule. Most
black-powder cannon, other than howitzers, seacoast howitzers and
mortars, had bore lengths fifteen or sixteen times caliber. With an odd
bottle-shaped appearance and the absence of decorative rings, something
new to cannon design, the gun had a maximum outside diameter of four
feet. Two types of projectiles were provided, a 450-pound solid shot
and a 330-pound explosive shell carrying a 17-pound bursting charge.
Perhaps even more important than his casting procedure was
Rodman's development of progressive-burning gunpowder. When a cannon is
fired, the volume of the bore behind the projectile increases as the
projectile travels toward the muzzle. The normal black powder grain,
being irregular in shape, burns from the outside so that its burning
surface area continually decreases. Thus, in a normal black powder
cannon, initial breech pressure is the highest obtained; the forward
traveling projectile increases bore volume as the gunpowder burns at a
decreasing rate. Both occurrences reduce interior bore pressure.
Rodman proposed gunpowder pressed into hexagonal grains
perforated with several longitudinal holes so that as individual grains
burned both inside and out, albeit almost instantaneously, the burning
surface of each grain actually would increase. Rodman's powder did not
increase pressures, it simply maintained a higher bore pressure than
normal powder could maintain as the projectile traveled forward. The
logical result was an increased muzzle velocity of the projectile. With
charges of his hexagonal powder, Rodman's 15-inch gun, even with its
relatively low bore length to diameter ratio, fired its 330-pound shell
at a muzzle velocity of 1,735 feet per second, much faster than the
velocity achieved with any other gun, including many with bore length
to diameter ratios as high as 20 to 1. With a 50-pound charge of
hexagonal powder (two-fifths of the later standard 125-pound charge)
the 15-inch gun at 25 degrees elevation had a maximum range of 4,680
The Rodman gun was adopted as the standard heavy gun for
coastal artillery and in lighter versions for fortress and siege use.
During the Civil War the Federal Government purchased about 130
fifteen-inch, 445 ten-inch, and 213 eight-inch Rodman guns from Cyrus
Alger & Co. (Boston MA), Fort Pitt Foundry (Pittsburgh PA),
Seyfert, McManus & Co. (Reading PA) and West Point Foundry (Cold
Spring NY). Many more were cast post-war. Like the famed Gun Club of
Jules Verne's "Journey from the Earth to the Moon and Around It,"
Rodman wanted an even bigger gun to test, and he proposed building one
as soon as the first 15-inch had been accepted. In his report to the
War Department dated 17 April 1861, he expressed no doubt that a
reliable cannon of almost any size could be made with complete success.
20-inch Rodman gun, Model of 1861
Rodman felt, or at least claimed (he seems to have limited his
ambitions rather reluctantly), that a 20-inch gun firing a half-ton
shot would be quite big enough. Anything larger would require massive
machinery for loading, and "it is not deemed probable that any naval
structure, proof against that caliber, will soon if ever be built...."
Rodman's newest monster, one of the largest iron castings (to say
nothing of the largest cannon) ever attempted, was three years in the
making. Expected to weigh over 100,000 pounds finished, the gun was
much heavier than the 40-ton capacity of Knap, Rudd's largest furnace.
The foundry, however, had a total pouring capacity of 185 tons and
expected to cast the new gun from six furnaces at once. New plans had
to be drawn, molds had to be made, new casting procedures were
essential, and new finishing machinery had to be designed and built.
The great day finally arrived on 11 February 1864. With Major
Rodman, then superintendent of Watertown Arsenal MA, supervising the
operation, the huge gun was cast. Filled in sequence from different
furnaces, the four-piece mold took 160,000 pounds of molten iron.
Cooling, by both running water and streams of air, took nearly a week,
after which the gun was finished on a specially built lathe. The muzzle
of the gun was inscribed: "No.1 116,497lbs / FORT PITT PA 1864."
Destined for Fort Hamilton in New York harbor, the gun was placed on a
double-trucked railroad flatcar, also specially built, at the foundry
to await shipment. As the Pittsburgh Gazette reported on 23 July 1864,
"Juveniles, aged from ten to fifteen years, were amusing themselves
today in crawling into the bore on their hands and knees. A good sized
family including ma and pa, could find shelter in the gun and it would
be a capital place to hide in case of a bombardment...." Rodman
supervised the building of a special carriage for the 20-inch gun at
Watertown Arsenal. The finished product, an iron front pintle barbette
carriage weighing 36,000 pounds, was shipped off to New York and
assembled at Fort Hamilton.
8-inch Rodman gun, Model of 1861. Total length, 123.5 inches;
weight, 8490 pounds; total production, 148 at Fort Pitt Foundry and
Seyfert, McManus & Co. 1861-65; known survivors: 40. An additional
65 8-inch Rodman prototype guns were cast at Fort Pitt and West Point
foundries in 1861 of which there are 16 known survivors. These have
elevating ratchets rather than the elevating sockets of the Model of
1861 (see below).
Rodman prototype elevating ratchets. The first 65 8-inch, the
first 10 10-inch, and the first 15-inch Rodman cast had elevating
ratchets like Columbiads, Models of 1842, 1844, 1857, and Confederate
Rodman Model of 1861 elevating sockets. All Rodmans cast after
21 February 1861 had elevating sockets similar to those shown here.
Each foundry casting Rodmans used slightly different radii at the
socket corners and can be identified by this feature.
10-inch Rodman gun, Model of 1861. Total length, 136.66
inches; weight, 15,050 pounds; total production, 1,291 at Alger, Fort
Pitt, West Point foundries and Seyfert, McManus & Co. 1862-67;
known survivors, 99. An additional 10 10-inch Rodman prototypes, with
elevating ratchets like those pictured above, were cast at Fort Pitt
Foundry in 1861. There is no known survivor. As with the 8-inch Rodman
prototypes detailed above, the prototypes had elevating ratchets rather
than the elevating sockets of the later Model of 1861.
10-inch Rodman gun, sleeved to 8-inch rifle. 210 existing
10-inch Rodmans were sleeved to 8-inch rifles via both muzzle and
breech insertion. These alterations were effected at South Boston
(Alger) and West Point foundries from 1876 to 1887. Wrought-iron
sleeves were first used, with steel sleeves used later. These
variations resulted in three series of new Registry Numbers, and
original muzzle face markings were removed and replaced with new
markings. Of the 99 known surviving 10-inch Rodmans mentioned above, 46
have been sleeved to 8-inch rifles. Except for the bore diameter, the
presence of rifling (15 or 24 grooves), and muzzle markings, those
sleeved via muzzle insertion have an external appearance exactly like a
unaltered 10-inch Rodman.
Muzzle face of 10-inch Rodman gun, sleeved to 8-inch rifle. If
there are not too many layers of paint on it, the initials of the
company making the sleeve, and of the person inspecting it at that
company, can be seen on the middle of the three rings that now appear
to form the surface of the muzzle face.
10-inch Rodman gun, evidence of breech insert. 27 10-inch
Rodmans were altered to 8-inch rifles at South Boston Foundry (Alger)
in 1879 using steel sleeves with 15-groove rifling. The same foundry
altered an additional 47 10-inch Rodmans in 1884 using steel sleeves
with 24-groove rifling. From this total of 74 guns sleeved via breech
insertion, the 14 known survivors have a conspicuous square extension
of the threaded breech plug. This provided purchase for the wrench used
to tighten the breech plug.
15-inch Rodman gun, Model of 1861. Total length, 190.0 inches;
weight, 50,000 pounds; total production, 323 (including one prototype)
by Cyrus Alger, Fort Pitt Foundry, and Seyfert, McManus & Co. from
1861 to 1871. Known survivors, 25, including the prototype cast at Fort
20-inch Rodman gun, Model of 1861. Total length, 243.5 inches;
weight, 116,497 pounds; total production for U.S. Army Ordnance, 2;
known survivors, 2. The first 20-inch Rodman was completed at Fort Pitt
Foundry in August 1864 and survives outside Fort Hamilton at Brooklyn
NY. The second was cast at Fort Pitt Foundry in 1869 and survives at
Fort Hancock NJ. A third was later cast at Fort Pitt Foundry and sold
to the government of Peru.
8-inch Confederate Columbiad gun. Total length, 120.0 inches;
weight, 8750 pounds. The total quantity of these guns cast is unknown
although 69 were cast at Tredegar Foundry from June 1861 through
December 1863. About the same quantity were cast at Bellona Foundry. At
least six, and probably more, of this pattern were bored and finished
as 5.82-inch rifles. There are 7 known survivors, all smoothbores.
10-inch Confederate Columbiad gun. Total length, 123.5 inches;
weight, 13,500 pounds; The total quantity of these guns cast is unknown
although 128 were cast at Tredegar Foundry from May 1861 through
January 1865. Perhaps 70 were cast at Bellona Foundry during that same
period. Several were bored and finished as 6.4-inch rifles. Known
survivors, 19, including one bored as a 6.4-inch rifle.
8-inch rifle bored from 10-inch Confederate Columbiad gunblock and double banded.
Tredegar 10-inch Columbiad castings Nos.1965 and 1977 were cast in
November 1863. They were bored and finished as 8-inch rifles, then
double banded. The finished weights, after rifling but prior to
banding, were 15,043 and 15,250 pounds, respectively. One of those two
tubes is shown in this wartime photo taken at an unidentified location.