155 mm Long Tom

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M1 155 mm Long Tom
Long Tom in travelling position, US Army Ordnance Museum.
Type	Towed field artillery
Place of origin	United States
Service history
Used by	United States, Austria, South Korea, Taiwan, Turkey
Wars	Second World War
Production history
Designed	1930s
Specifications
Weight	13,880 kg (travelling)
Barrel length	45 calibres
Crew	14
Caliber	155 mm (6.1 inch)
Breech	Ashbury breech
Carriage	M1 Carriage
Elevation	−2°/+65°
Traverse	60°
Rate of fire	40 rounds per hour
Muzzle velocity	853 m/s
Maximum range	23,221 m

See also: 155 mm Creusot Long Tom

The 155 mm Gun M1 and M2 (later M59), widely known as Long Tom, were 155 millimeter calibre field guns used by the United States armed forces during World War II. The Long Tom replaced the Canon de 155 mm GPF in United States service.

Contents 1 Development 2 Service 3 Variants 4 Ammunition 5 Notes 6 References

[edit] Development

Before entering World War I, the United States was poorly equipped with heavy artillery. To address this a number of foreign heavy artillery guns were adopted, including the Canon de 155 mm GPF. After the end of the war development work began in the United States on a design to improve upon the existing models of heavy gun and carriage. A number of prototypes were produced in the 1920s and 1930s, but the projects were put on hold due to lack of funds. In 1938 the 155 mm Gun T4 on Carriage T2 was finally adopted as 155 mm gun M1 on Carriage M1.

The new design used a barrel broadly similar to the earlier 155 mm GPF, but with an Ashbury breech. The new split-trail carriage featured four roadwheels, each mounting two tires. The wheels could be lifted, allowing the gun to rest on a firing platform. This made the gun very stable and thus accurate.

The gun was developed into M1A1 and M2 variants. After the war, the United States Army re-organized, and the gun was redesignated as the M59.

[edit] Service

The Long Tom saw combat for the first time in North African Campaign in 1943, with 34th Field Artillery Battalion. Eventually it equipped about 49 battalions, including 40 in the European Theater and 7 in the Pacific. The preferrable prime mover was initially the Mack NO 6x6 7 1/2 ton truck; from 1943 it was replaced by the tracked M4 High Speed Tractor.^[1]

A small number of Long Tom guns were supplied via lend lease channels, to the United Kingdom (184) and France (25).^[2]

[edit] Variants

Gun variants:

• M1920 - prototype.
• T4 - prototype.
• M1 (1938) - first production variant, 20 built.
• M1A1 (1941) - modified breech ring.
  • M1A1E1 - prototype with chromium plated bore.
  • M1A1E3 - prototype with liquid cooling.
• M2 (1945) - modified breech ring.

Carriage variants:

• T2 - prototype.
• M1 (1938).
• M1A1 - refurbished T2 carriages.

The gun was also mounted on a modified M4 medium tank chassis, in mount M13. The resulting vehicle was initially designated 155 mm Gun Motor Carriage T83 and eventually standardized as 155 mm Gun Motor Carriage M40.^[3]

155 mm Gun Motor Carriage T79, based on T23 Medium Tank chassis, never advenced past proposal stage.^[4]

[edit] Ammunition

The gun utilized separate loading, bagged charge ammunition. The propelling charge consisted of base (9.23 kg) and increment (4.69 kg). The data in the table below is for supercharge (base and increment).

Projectiles.[3][5][6]
Type	Model	Weight, kg	Filler	Muzzle velocity, m/s	Range, m
APBC/HE	AP M112 Shell	45.36	Explosive D	837	22,014
HE	HE M101 Shell	42.96	TNT	853	23,513
Smoke	WP M104 Shell	44.53	White phosphorus (WP)	853	23,720
Smoke	FS M104 Shell		Sulfur trioxide in Chlorosulfonic acid	853	23,720
Chemical	H M104 Shell		Mustard gas, 5.3 kg	853	23,720
Dummy	Dummy Mk I Projectile		-	-	-
Dummy	Dummy M7 Projectile	43.09	-	-	-

 

Armor penetration, mm[3]
Ammunition \ Distance, m	457	914
AP M112 Shell (homogeneous armor, meet angle 30°)	160	152
AP M112 Shell (face hardened armor, meet angle 30°)	135	130
Concrete penetration, mm[3]
Ammunition \ Distance, m	914	4572
HE M101 Shell (meet angle 0°)	2,011	1,402
Different methods of measurement were used in different countries / periods. Therefore, direct comparison is often impossible.

[edit] Notes

1. ^ Zaloga - US Field Artillery of World War II, p 20-22.
2. ^ Zaloga - US Field Artillery of World War II, p 37.
3. ^ ^{a b c d} Hunnicutt - Sherman: A History of the American Medium Tank, p 353-355, 570.
4. ^ Hunnicutt - Pershing, A History of the Medium Tank T20 Series, p 158.
5. ^ Technical Manual TM 9-1901, Ammunition, p 197-202.
6. ^ Technical Manual TM 9-1904, Ammunition Inspection Guide, p 490-518.

[edit] References

• Bishop, Chris. Encyclopedia of Weapons of World War II. 
• Hunnicutt, R. P. (1994). Sherman: A History of the American Medium Tank. Presidio Press. ISBN 0-89141-080-5. 
• Hunnicutt, R. P. (1996). Pershing, A History of the Medium Tank T20 Series. Feist Publications. ISBN 1-112-95450-3. 
• Zaloga, Steven J. (2007). US Field Artillery of World War II, illustrated by Brian Delf, New Vanguard 131, Osprey Publishing. ISBN 978-1-84603-061-1. 
• Technical Manual TM 9-1901, Artillery Ammunition. War Department, 1944. 
• Technical Manual TM 9-1904, Ammunition Inspection Guide. War Department, 1944. 

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