280mm Gun Information Folder/Packet at the Dwight D. Eisenhower Presidential Library





Index

1. Cost Data

2. Deployment Schedules and Readiness Dates

3. Status of Guns and Shells

4. Weapons Characteristics

5. Pro's and Con's of the 280m Gun

6. Ordnance Corps Unclassified Fact Sheet.

7. 280mm Gun Test Data





- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -



COST DATA

ITEM

PRICE

280mm gun complete w/spares

$1,000,000

280mm tube

$196,000

Transporter

$363,000

Atomic Rd. (Complete)

(DELETED)

Non-nuclear components of Atomic Rds.

$18,000

HE Rd.

$688

Development Costs to the Army


Gun

$3,018,000

HE Shells

$2,834,000

Atomic Shells

$576,000

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -



DEPLOYMENT AND READINESS SCHEDULE

European Area

CINCEUR has asked for 6 Bns in his pre D-day forces.

CINCSOUTH has informally expressed interest.

The Chief of Staff has approved the deployment of 2 Bns to EUCOM during July and August.

Tentative plans are for a total of 5 Bns to be deployed to EUCOM during first half of FY 54.

Deployments to CINCSOUTH are under study in G-3.

FECOM

CINCFE has asked for 1 Bn.

Deployments to Korea are under Study in G-3.

ZI

Organization

Location

Estimated Readiness Date
FY ‘54

1

2

3

4

367th FA Bn

Ft Sill

X




868

Ft Bragg

X




264

Ft Sill

X




265

Ft Bragg

X




59

Ft Sill


X



216

Ft Sill


X



663

Ft Bragg




X

692

Ft Sill




X

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

STATUS OF GUNS AND SHELLS

I    280 Gun




PRODUCTION





Total

Received

Accepted by Ord.

280mm gun, w/carriage

60

56

19

due in May


4






Transporters, prs.

66

66

30

Extra Tubes

40

0






ISSUES





Quantity



4 Bns, Fort Sill

10



3 Bns, Fort Bragg

7



AFF Bd No. 1 Ft. Bragg

    1    




18







IN ORDNANCE HANDS

38







II    HE SHELL




PRODUCTION SCHEDULE


Quantity


As of 30 April '53


654


As of 31 Dec '53


10,854


Total Requirements, Jan ‘55


37,400






- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

WEAPON CHARACTERISTICS

280mm Gun

Width:

10 ft.

Height:

12 ft.

Length:

85 ft.

Weight:

85 tons

Emplaced Weight:

48 tons

Maximum Speed:

35 mph.

Transportability:

Can be transported on several types of landing craft (LSM, LSU, LCT, some LST's)

Can use division bridge

Can negotiate right angle turn at intersection of 228 ft. streets

Range:

Atomic Rd: 26,500 yards (by the end of CY 54 32,000)

HE Rd: 32,000 yards (development continues on 8" sabot rd., 45,000 yds)

Estimated Tube Life:

800 to 1000 rounds (scratched out and replaced with 600 to 800)

Accuracy:

1/48 in range
1/2 mil in deflection

Rate of Fire:

1 round in 2 minutes

Fuze:

3 Mech, time, first to fire

Safing:

Positive safing for 3000 yards of trajectory

Atomic Shell. MK 9

Weight:

800 lbs

Yield:

[DELETED]

Mod 1 will:

[DELETED]

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

PRO’s and CON’s of the 280mm Gun

CON

PRO

[DELETED]

Agreed. When F84's can adequately and safely complete atomic missions they will be used. Weather, safety, and air superiority nay preclude air delivery being used.


The 280mm gun lacks mobility.

Special routes and engineer assistance in route preparation will generally be required. Most large military targets are on natural routes of advance rather than inaccessible terrain. The gun can be transported in standard amphibious vehicles, can cross beaches, and can use the standard division bridge.


[DELETED]

It is not necessary to have a nuclear component at each gun. Normally these components will be centralized in each Army area. When targets are anticipated the material can be sent to the gun battalions by jeep or helicopter.


Those guns will be a prime target and be quickly destroyed by the enemy.

It is agreed that our 280 atomic capability would rank right after our air atomic capability as a priority target. Undoubtedly some of these guns will be destroyed but they are much more easily camouflaged and much more resistant to damage than aircraft. Further they will not be destroyed while carrying fissionable material as will happen to some of our aircraft.


Guided missiles and rockets have an all weather capability and can do the job more cheaply.

Their all weather capability remains to be demonstrated. Likewise their reliability and accuracy are not fully developed.

The 280mm gun's primary role is, as a conventional artillery piece, to fulfill the requirement for long range artillery.


- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -



ARMY ORDNANCE CORPS
23 September 1952

FACT SHEET
Army's New
Artillery Piece

I. Nomenclature:

Gun, 280mm, T131
Carriage, 280mm Gun, T72
Transporter, 280mm Gun, T10

II. Significant Features of the Weapon Which Represent Important Advances in Army Ordnance Material:

1. This 280mm gun is the Amy's largest-caliber artillery piece having complete mobility.
2. It is an artillery piece for firing both conventional and atomic shells.
3. It can deliver an atomic shell on target in all kinds of weather, day or night, unlike an air-delivered atomic bomb.
4. It can fire with accuracy comparable to conventional artillery in the shorter ranges and is considered to be much more accurate at long ranges – four times more accurate at long ranges than any mobile artillery pieces developed prior to World War II.
5. It is carried suspended between two engine cabs, front and roar, which can transport their load on highways at a speed of about 35 miles per hour.
6. It is equipped with telephones to permit communication between front and roar drivers while on the move, with the loading transporter driver having control of throttle and brakes for both units although both can be operated independently.
7. Although the complete unit ready for traveling weighs about 85 tons, it is not much larger than the heaviest field artillery piece now in service, and can cross bridges capable of carrying any standard piece of equipment in an Army Division.
8. It can travel cross-country as well as on the highways and can fit into a landing ship designed for amphibious operations.
9. It can be emplaced and put into action with greater speed than any other heavy field artillery pieces now in use.
10. The gun is so balanced in the vertical by a hydro-pneumatic equilibrator system that one man can elevate or depress it by exerting a pressure of not more than 30 pounds or a hand-wheel in case of failure of the power unit normally provided.
11. The entire carriage is balanced on a turntable equipped with a large steel ball that fits a socket in the carriage, plus three jacks with wheels which ride a track around the circumference of the turntable. When jacked up in the rear, the carriage can be rotated horizontally through a complete circle. A gear train operated by a handwheel on which no more than 10 pounds of pressure need be exerted traverses the weapon through a smaller arc. The jacks also make it possible to level the gun on uneven terrain.
12. The projectile and powder charge are loaded into the weapon's breech by means of a hydraulic power rammer though this operation may also be performed by hand.
13. The gun can give a kind of accurate and devastating close support to ground troops never before available to them in the history of warfare.

III. Characteristics of Gun and Carriage.

1. Range - about 20 miles.
2. Ammunition - High Explosive and other conventional types in addition to atomic shell.
3. Elevation - 0 to 55 degrees.
4. Traverse - 360 degrees.
5. Length of carriage (without transporters) - 38.5 feet.
    Length overall (including transporters) - 84 ft., 2 inches.
6. Weight - Approximately 85 tons - complete unit.

IV. Characteristics of the T-10 Transporter (Comprising the two end-units).

1. Each unit is powered by a six-cylinder Ordnance-Continental air-cooled gasoline engine of 375 gross horsepower.
2. These six-wheeled 4x4 units (dual wheels in the rear) which pick up and carry the gun between them, can operate completely independent of each other, but when the carriage and mount assembly is attached, the forward unit has control of the throttle and brakes for both units. The "A" or front tractor unit has its cab forward in the manner of conventional trucks, while the "B" or rear tractor has its cab at the back of the unit.
4. The payload of the T-10 Transporter is approximately 50 tons. (The largest Western highway trucks have a payload of less than half that amount.)
5. Large carrying capacity in proportion to weight has been achieved through extensive utilization of high tensile, high carbon steels and aluminum. These metals wore used not only to accomplish weight reduction but to conserve steel.
6. Although the unit complete with transporters is 84 foot, 2 inches long (the longest conventional truck-trailer used on even Western highways is 60 feet), the transporters can make right angle turns with their load at city street corners where the streets are only 28 feet wide.
7. The unit as a whole can be moved forward, backward or sideways since either transporter can pull while the other pushes, or they can turn at right angles to the center section and proceed parallel to one another.

V. Additional Facts of Interest.

1. Size of parts vary from screws weighing one ounce to the top carriage weighing 16,000 lbs.
2. Nearly 2200 separate blueprints were required for the gun assembly alone, with accuracy of machining, even on the largest components, held to one-thousandth of an inch on critical dimensions.
3. The principal types of metal used in the carriage include several grades of carbon, high tensile, alloy and stainless steels plus aluminum, magnesium, bronze, copper, and brass.
4. History of Development:
The design of a heavy field artillery weapon which would overcome certain deficiencies that were encountered in World War II weapons was initiated by the Chief of Army Ordnance in November 1944.
A decision as to desired military characteristics was reached after a feasibility study of several months by artillery, ballistic and Ordnance exports in coordination with the Ordnance Sub-Office, Franklin Institute Philadelphia, Pa.
Technical supervision for preparation of the design and for manufacture of the carriage was officially assigned to Army Ordnance Watertown Arsenal, Watertown, Mass., in March 1947 and design preparations were immediately begun. Army Ordnance Watervliet Arsenal, Watervliet, New York, was at the same time assigned a like responsibility for the gun tube and breech. Direction and coordination of the overall project remained the responsibility of the Office Chief of Army Ordnance, with the actual designing operations at Franklin Institute jointly supervised by OCO and Arsenal representatives.
Manufacture of pilot model was begun in 1948.
In compliance with instructions from the Chief of Staff, U.S. Army, design of appropriate changes to accommodate an atomic charge was ordered in November 1949 by the Office of the Chief of Amy Ordnance. Preliminary designs prepared accordingly by Office Chief of Ordnance were then turned ever to Watervliet Arsenal for final detail, drafting and manufacture.
The first complete assembly with atomic firing capabilities was ready for testing in the spring of 1951.

5. Principal agencies contributing to production of the Unit:

a. Prime Contractor
Franklin Institute, Philadelphia, Pa.
Primary layout and engineering
Dravo Corporation, Pittsburgh, Pa.
Manufacture of Gun Carriage
R. Hoe & Co., New York, N. Y.
Manufacture of Gun Recoil Mechanism
Kenworth Motor Truck Corp., Seattle, Wash.
Manufacture of Gun Transporters
Baldwin-Lima-Hamilton Corp., Eddystone, Pa.
Manufacture of Gun Carriage
Treadwell Construction Co., Midland, Pa.
Manufacture of Gun Carriage
b. Army Ordnance Installations:
Watertown Arsenal, Watertown, Mass.
Project supervision plus manufacture of carriage and recoil mechanism.
Watervliet Arsenal, Watervliet, N.Y.
Production and machining of gun tube.
Frankford Arsenal, Philadelphia, Pa.
Adaptation of Fire Control Instruments
Detroit Arsenal, Detroit, Mich.
Design and development of Transporters.
Picatinny Arsenal, Dover, N.J.
Development of ammunition.
Aberdeen Proving Ground, Md.
Design criteria and development testing.

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Copy

280mm GUN TEST DATA

MUZZLE VELOCITY PLUS METRO

ERROR OF VERIFYING ROUND


DIRECTION
(Epd = 2.4 yds)

RANGE
(Epr = 59 yds)

HEIGHT
(Eph = 36 ft)

Test 1, Ft. Sill phase

L 24

-41

-113

Test 2, Ft. Sill phase

R 22

±126

-121

Test 3, Ft. Sill phase

R 11

±35

- 63

Test 1, NPG phase

0

±17

-167

SUMMARY OF RESULTS

MINIMUM AND MAXIMUM ERROR OF VERIFYING ROUNDS

METHOD

DIRECTION
(Epd = 2.4yds)

RANGE
(Epr = 59 yds)

HEIGHT
(Eph = 36 ft)

HIGH BURST REG

L 12

-14

±20

R 22

±125

-104

ONE SPOTTING ROUND ADJUSTMENT

R 11

±18

±32

L 24

-58

±58

MUZZLE VELOCITY PLUS METRO

R 11

±35

-63

R 22

±126

-121

SILENT ADJUSTMENT

0

- 9

±92

R 44

±173

±4

Added: 25 May 53 1st Round fired at 0544 hours.

Using predicted fire procedure (met ± MV), for the 1st Round of the registration the error was (In terms of ground zero):


Dir

Rn

Rt

ERROR

R 28 yds

- 70 yds

±13 yds

Value of 1 PE

2.4 yds

59 yds

13 yds

DELETED

DELETED

DELETED

DELETED

/s/ B.S.Spivy
Col, Arty.