The medium size M198 replaced the well reguarded M114 that was developed in the 1930's. A continuing need to upgrade howitzers that could send projectiles down range at increased distances and have excellent elevation for over head plunging fire was the M198. This upgrade also needed adaptability to accept and fire all types of NATO 155 mm rounds by the contractor, the Rock Island Arsenal. Additional ammunition offered for the M198 include anti tank mine rounds, laser guided shells designed for stationary or moving targets, high explosive anti personnel grenades, illumination rounds, smoke and tactical nuclear round out the diverse weapon package.
With the Viet Nam war winding down the first prototype XM198 started testing trials. In 1979 the US Army received their first battalion delivery of 18. Soon after, the U.S.M.C. and Australia and some Middle Eastern armies placed battalion size orders.
The M198 is not a self propelled howitzer and is towed by a 5 ton truck that is used to carry the 9 man crew with supplies and ammunition. Other wheeled vehicles in the U.S. motor pool can handle the M198 along with the air mobility arm using the US Army Chinook CH-47C and the U.S.M.C. Super Stallion CH-53E. The howitzer is slung underneath for transport or be dropped by parachute to support ground forces.
The major parts of the M198 is the split tail carriage using an upgraded suspension system, The 155mm cannon is the M199 that uses a screw type breech and a thermal warning device. To fire the platform is lowered to the ground and the wheels are raised off the ground. Along with the split tail carriage this gives three point stability. The fire control system uses the M137 panoramic telescope.
In a combat role the M198 was used in the Middle East and Lebanon. With continued improvement programs the M198 is the standard 155 mm howitzer for the US Army and the US Marine Corps and will be used into the 21st Century.
Ranges for the M107 and M540A1 (rocket-assisted) projectiles is reported to be 19,850 yards and 32,810 yards repectively. Elevation is -5 degrees up to +72 degrees with a traverse of 45 degrees. A rate-of-fire of 4 rounds-per-minute can be achieved along with 2 rounds-per-minute sustained.
- Fire Support / Assault / Breaching
40.49 ft (12.34 m)
9.15 ft (2.79 m)
9.51 ft (2.9 m)
8 tons (7,163 kg; 15,792 lb)
11,278 miles (18,150 km)
1 x 155mm gun barrel.
Dependent on ammunition carrier.
XM198 - Prototype and Trials Model Designation
M198 - Production Designation