M55
Overview
M55 self-propelled howitzer
Former US military M55 self-propelled howitzer on display at the United States Army Ordnance Museum as seen in 2007.
Source: Mark Pellegrini -
© CC BY-SA 2.5
1956 - ? (conversion of M53 to M55)
100+ M53 converted to M55
T108 (prototype)
West Germany
Belgium
Turkey
Italy
Description
Introduction
The M55 is an early Cold War era self-propelled howitzer of US origin. It was developed in the early 1950's by Pacific Car and Foundry. with the mount to be universal for both a 155mm gun or a 203mm howitzer. The 155mm version was adopted first and was known as the M53. The M55 entered service one year later in 1953.
Design
The M55 shares a high level of commonality with the M47 Patton tank regarding the engine, transmission and tracks. The M55 is a very large and heavy vehicle. The engine and drivetrain are located at the front. Uniquely, the entire crew is housed in the turret. This includes the driver at the left front of the turret. He is seated on a revolving chair that remains facing in the direction of the hull as the turret rotates.
Firepower
The M55 is the 203mm howitzer variant. Maximum range is 16.9 km for high explosive shells. Rate of fire is rather low at 0.5 rpm. On board ammunition supply is very limited at only 10 shells with associated charges. For self-defense a 12.7mm M2HB heavy machine gun is mounted at the turret roof.
Protection
The M55 features a welded steel hull and turret. All around protection is 13mm. Only the front hull is thicker at 25mm. This protects the crew from small arms fire and shell splinters. The M55 is to be operated from under full armor protection. During the Vietnam War these were often used with the large rear turret doors in the open position.
Mobility
The M55 is a large and heavy vehicle with low fuel economy. The 810 hp petrol engine provides good mobility in the field at a high fuel consumption. Maximum speed is 53 km/h on road. Maximum range is limited at 240 km, despite having a 1.440 L fuel tank.
Users
The M55 was adopted by the US Army. It was not adopted by the US Marine Corps. Former US military M55s were exported to various NATO allies. These include West Germany, Italy, Belgium and Turkey. Last operational M55 were in Belgian service into the 1970's. In US service the M55 was replaced by the M110. The same also applies to most M55s in foreign service.
Factsheet
Related articles
M53
The M53 self-propelled gun uses the same chassis, turret and gun mount, but is armed with the long barrel 155mm L/45 gun.
M110
In US Army service the M55 was replaced by the M110 self-propelled howitzer.