M115 howitzer

For other uses, see M115 (disambiguation).

M-115 203 mm howitzer
A M-115 203 mm howitzer on display at Bastrop, Texas, United States.
Type	Howitzer
Place of origin	United States
Production history
Designed	1939
Specifications
Weight	14,515 kg (31,780 lbs)
Length
Barrel length
Crew	14
Shell	90.7 kg (200 lb)
Caliber	203 millimetres (8.0 in)
Breech	Interrupted screw
Recoil	Hydropneumatic
Carriage	Split trail
Elevation	−2° to +65°
Traverse	+60°
Rate of fire	1 rpm (maximum) 3 rounds per 2 minutes (maximum)
Muzzle velocity	587 m/s (1,926 ft/s)
Effective firing range	16,800 m (18,373 yds)

The M115 203 mm howitzer, also known as the M115 8 inch howitzer, was a towed howitzer developed and used by the United States Army. Until the 1950s it was designated the 8 inch Howitzer M1. The original design started in 1919 but lapsed until resurrected in 1927 as a partner-piece for a new 155 mm gun. It was standardized as 8 inch Howitzer M1 in 1940. The M115/M1 was towed by the M35 Prime Mover gun tractor or a Mack 7⅓ ton 6×6 truck.

Like the British BL 8 inch Howitzer of the First World War, the M115 uses a Welin screw for its breech. The carriage was the same as used for the US 155 mm gun and was also adopted by the British for their 7.2 inch Mark 6 howitzer. It consists of equilibrator assemblies, elevating and traversing mechanisms, two single-wheel, single-axle heavy limber, and a two-axle bogie with eight tires and two trails. Four spades, carried on the trails, are used to emplace the weapon. The British 8 inch howitzer was produced in England and under license in the US, for the American Expeditionary Forces in Europe during World War I, as the 8-inch Howitzer MK. VI. It was in service with the US Army till replaced by the M115. There are no reports of the MK. VI or another marks being used during World War II.

The first photos of the M115 type 8 inch cannon on its redesign carriage appeared in 1931 but development was slowed by the Great Depression.

The M115 saw U.S. service in World War II, the Korean War, and the Vietnam War. In the late 1950s, it was adopted in small numbers by several NATO armies, to fire the W33 (M454 shell) and later the W79 nuclear artillery shell, under the NATO nuclear sharing concept, a role which ended when the smallest types of tactical nuclear weapons were removed from service and eliminated. It was also adopted as a field weapon by a number of nations in Europe, the Middle East, and Asia and saw service in the Second Taiwan Strait Crisis and the Croatian War of Independence.

Operators

• United States
• Republic of China
• Croatia: former operator, 24 systems
• Denmark: former operator 1953–1992, 12 systems
• Greece: former operator
• Italy: 9° Gr.A.Pe. - Gruppo Artiglieria Pesante "Rovigo", 1° Gr.A.Pe. - Gruppo Artiglieria Pesante "Adige", Gruppo A.U.C.-T.M. - Allievi Ufficiali di Complemento a Traino Meccanico
• Iran
• Iraq
• Japan
• Republic of Korea: Many on DMZ
• Pakistan: About 28 in service
• Sudan: in Turkey, 60 systems
• Turkey

Self-propelling mounts

8 inch HMC M43 in Korea.

• The howitzer was mounted on a modified M4 medium tank chassis, in mount M17. The resulting vehicle was initially designated 8 inch Howitzer Motor Carriage T89 and eventually standardized as 8 inch Howitzer Motor Carriage M43. A total of 48 units were built.
• 8 inch Howitzer Motor Carriage T80 – based on T23 Medium Tank chassis, never advanced past proposal stage.
• 8 inch Howitzer Motor Carriage T84 – based on T26 Medium Tank chassis, a single pilot was built in 1945.
• The howitzer was mounted on a purpose-built tracked chassis to become the 8 inch Self-Propelled Howitzer M110. Notably accuracy and rate of fire suffered from having to depress the cannon tube to loading elevation for each round in order to use the track-mounted auto loader.

Ammunition

The howitzer fired separate loading, bagged charge ammunition, with seven different propelling charges, from 1 (the smallest) to 7 (the largest). The M454 Nuclear shell had its own M80 cartridge with three propelling charges.

Projectiles.
Type	Model	Weight	Filler	Muzzle velocity	Range
HE	HE M106 Shell (charge M2)	90.7 kg (200 lb)		594 m/s (1,950 ft/s)
HE	HE Mk 1A1 Shell (charge M1)	90.7 kg (200 lb)		408 m/s (1,340 ft/s)
Dummy	Dummy Mk 1 Projectile		—	—	—

 

Propelling charges.
Model	Weight, complete	Components
M1 ("green bag")		Five incremental charges (for charges 1 to 5)
M2 ("white bag")		Base charge and two incremental charges (for charges 5 to 7)
M4 (dummy)		Base charge and two incremental charges

 

Concrete penetration
Ammunition / Distance
HE M106 Shell (meet angle 0°)
Different methods of measurement were used in different countries / periods. Therefore, direct comparison is often impossible.

See also

• 203 mm howitzer M1931 (B-4)—approximate Soviet equivalent
• BL 7.2-inch howitzer—British equivalent
• List of U.S. Army weapons by supply catalog designation—SNL D-29

References

• Missing Lynx
• TM 9-2300 Standard Artillery and fire Control Material (dated Feb. 1944)
• TM 9-335
• TM 9-1350

External links

• Media related to M115 203 mm howitzer at Wikimedia Commons