The M198 is a medium-sized, towed

155 mm 155 mm (6.1 in) is a common, NATO-standard, artillery caliber. It is defined in AOP-29 part 1 with reference to STANAG 4425. It is commonly used in field guns, howitzers, and gun-howitzers. Land warfare The caliber originated in France after ...

artillery Artillery is a class of heavy military ranged weapons that launch munitions far beyond the range and power of infantry firearms. Early artillery development focused on the ability to breach defensive walls and fortifications during siege ...

piece, developed for service with the

United States Army The United States Army (USA) is the land service branch of the United States Armed Forces. It is one of the eight U.S. uniformed services, and is designated as the Army of the United States in the U.S. Constitution.Article II, section 2, cla ...

and

Marine Corps Marines, or naval infantry, are typically a military force trained to operate in littoral zones in support of naval operations. Historically, tasks undertaken by marines have included helping maintain discipline and order aboard the ship (refle ...

. It was commissioned to be a replacement for the World War II-era

M114 155 mm howitzer The M114 is a towed howitzer developed and used by the United States Army. It was first produced in 1942 as a medium artillery piece under the designation of 155 mm Howitzer M1. It saw service with the US Army during World War II, the Korean ...

. It was designed and prototyped at the

Rock Island Arsenal The Rock Island Arsenal comprises , located on Arsenal Island, originally known as Rock Island, on the Mississippi River between the cities of Davenport, Iowa, and Rock Island, Illinois. It lies within the state of Illinois. Rock Island ...

in 1969 with firing tests beginning in 1970 and went into full production there in 1978. It entered service in 1979 and since then 1,600 units have been produced. The M198 was replaced in US and Australian service by the

M777 howitzer The M777 howitzer is a British towed 155 mm artillery piece in the howitzer class. It is used by the ground forces of Australia, Canada, Colombia, India, Saudi Arabia, Ukraine, and the United States. It was first used in combat during the US w ...

Description

The M198 155 mm

howitzer A howitzer () is a long- ranged weapon, falling between a cannon (also known as an artillery gun in the United States), which fires shells at flat trajectories, and a mortar, which fires at high angles of ascent and descent. Howitzers, like ot ...

weighs less than , allowing it to be dropped by

parachute A parachute is a device used to slow the motion of an object through an atmosphere by creating drag or, in a ram-air parachute, aerodynamic lift. A major application is to support people, for recreation or as a safety device for aviators, who ...

or transported by a

CH-53E Super Stallion The Sikorsky CH-53E Super Stallion is a heavy-lift helicopter operated by the United States military. As the Sikorsky S-80, it was developed from the CH-53 Sea Stallion, mainly by adding a third engine, adding a seventh blade to the main rotor, ...

CH-47 Chinook The Boeing CH-47 Chinook is a tandem rotor helicopter developed by American rotorcraft company Piasecki Helicopter, Vertol and manufactured by Boeing Rotorcraft Systems#Background, Boeing Vertol. The Chinook is a heavy-lift helicopter that is a ...

. The M198 is a towed howitzer that is transported tail first. The gun tube can be rotated over the howitzer's trail legs to reduce its length, though this requires removal of the

muzzle brake A muzzle brake or recoil compensator is a device connected to, or a feature integral to the construction of, the muzzle or barrel of a firearm or cannon that is intended to redirect a portion of propellant gases to counter recoil and unwanted ...

, or left in the firing position for faster deployment. When firing, the weapon is lowered onto its baseplate rather than being anchored to the ground, allowing for rapid emplacement. The breech is operated manually via a screw type mechanism that rests low in an ergonomic position. The M198 fires separate-loading (non-fixed) ammunition and can be loaded with a variety of propellants and projectiles. The effective range is 18.1 kilometers when firing standard projectiles, which increases to 30 kilometers when firing rocket-assisted projectiles and guided ammunition. With the 52-caliber modification the range can surpass 40 kilometers. The weapon system requires a crew of 9 and is capable of firing at a maximum rate of four rounds per minute, two sustained. The M198 was deployed in separate

corps Corps (; plural ''corps'' ; from French , from the Latin "body") is a term used for several different kinds of organization. A military innovation by Napoleon I, the formation was first named as such in 1805. The size of a corps varies great ...

- and

army An army (from Old French ''armee'', itself derived from the Latin verb ''armāre'', meaning "to arm", and related to the Latin noun ''arma'', meaning "arms" or "weapons"), ground force or land force is a fighting force that fights primarily on ...

-level field artillery units, as well as in artillery

battalion A battalion is a military unit, typically consisting of 300 to 1,200 soldiers commanded by a lieutenant colonel, and subdivided into a number of companies (usually each commanded by a major or a captain). In some countries, battalions are ...

s of

light Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 tera ...

and

airborne Airborne or Airborn may refer to: Arts, entertainment, and media Films * ''Airborne'' (1962 film), a 1962 American film directed by James Landis * ''Airborne'' (1993 film), a comedy–drama film * ''Airborne'' (1998 film), an action film sta ...

divisions. It provided field artillery fire support for all

Marine Air-Ground Task Force Marine Air-Ground Task Force (MAGTF, pronounced MAG-TAF) is a term used by the United States Marine Corps to describe the principal organization for all missions across the range of military operations. MAGTFs are a balanced air-ground, combined ar ...

organizations until the adoption of the M777 howitzer.

Ammunition types

;High Explosive (HE) :( M-107 NC/DC): Explosive

Composition B Composition B, colloquially Comp B, is an explosive consisting of castable mixtures of RDX and TNT. It is used as the main explosive filling in artillery projectiles, rockets, land mines, hand grenades and various other munitions. It was also use ...

material packed into a thick, internally scored shell which causes a large blast and sends razor-sharp fragments at extreme velocities (5,000–6,000 meters per second). The kill zone has an approximate radius of 50 meters, and the casualty radius is 100 meters. The Marine Corps and US Army also uses th
M795
High Explosive round. ;Rocket Assisted Projectile (RAP) : A rocket-assisted HE (also known as H.E.R.A.)

M549 The M549 is a High-Explosive Rocket Assisted (HERA) 155 mm howitzer round developed for use by the US Military in order to add additional range to standard howitzers, with a maximum range 30.1 km from a M198 howitzer. The projectile has two dis ...

round that exceeds the maximum range of the normal HE. For the 155 mm RAP round, max range is . ;White Phosphorus (WP) : A base-ejecting projectile which can come in two versions: felt-wedge and standard.

White phosphorus Elemental phosphorus can exist in several allotropes, the most common of which are white and red solids. Solid violet and black allotropes are also known. Gaseous phosphorus exists as diphosphorus and atomic phosphorus. White phosphorus White ...

smoke is used to start fires, burn a target, or to create smoke which is useful in concealing the movements of friendly units. ;Illumination : Illumination projectiles are base-ejecting rounds which deploy a bright parachute flare ideally 600 meters above the ground and illuminate an area of approximately 1 grid square (1 square kilometer). Illumination rounds are often used in conjunction with HE rounds to illuminate the target area so that HE rounds can be fired more effectively. Illumination rounds can also be used during the daytime to mark targets for aircraft. The M485 illumination round burns for 120 seconds. ; Dual-Purpose Improved Conventional Munition (DPICM) : A base-ejecting projectile that drops 88 bomblets above a target. Each bomblet has a shaped-charge munition capable of penetrating two inches of solid steel as well as a fragmentation casing which is effective against infantry in the open. The DPICM round is effective against

armored vehicles Armour (British English) or armor (American English; see spelling differences) is a covering used to protect an object, individual, or vehicle from physical injury or damage, especially direct contact weapons or projectiles during combat, or f ...

, even

tank A tank is an armoured fighting vehicle intended as a primary offensive weapon in front-line ground combat. Tank designs are a balance of heavy firepower, strong armour, and good battlefield mobility provided by tracks and a powerful engin ...

s (since the deck armor is usually the thinnest on the vehicle), and is also extremely useful against entrenched infantry in positions with overhead cover. ; Area Denial Artillery Munition System (ADAMS) : An artillery round that releases anti-personnel mines. These mines eject tripwires to act as booby traps, and when triggered are launched upward before exploding. They are designed to self-destruct after a pre-determined period. ;Remote Anti Armor Mine System (RAAMS) : An artillery round that releases anti-armor mines, usually used along with ADAMS rounds to prevent the antitank mines from being removed. Designed to self-destruct after a pre-determined period. ;

Copperhead Copperhead may refer to: Snakes * ''Agkistrodon contortrix'', or copperhead, a venomous pit viper species found in parts of North America * '' Austrelaps'', or Australian copperhead, a genus of venomous elapids found in southern Australia and Ta ...

: An artillery launched guided high-explosive munition used for very precise targeting of high-value targets such as tanks and fortifications. No longer produced or used by the US military, it required the target to be designated with a laser designator system. ;

Sense and Destroy ARMor Project Sense and Destroy ARMor, or SADARM, is a United States 'smart' submunition capable of searching for, and destroying tanks within a given target area. History Beginnings SADARM development can be traced back to the early 1960s. The ori ...

(SADARM) : An experimental munition fired in the general direction of an enemy vehicle. The shell activates at a certain point in time ejecting a parachute and then guides itself to the nearest vehicle. ; XM454 AFAP (artillery fired atomic projectile) (W48) : The XM454 AFAP (W48) nuclear artillery shell had a 155mm caliber and an explosive yield of only . All units were retired from service in 1992.

Replacement

BAE Systems BAE Systems plc (BAE) is a British multinational arms, security, and aerospace company based in London, England. It is the largest defence contractor in Europe, and ranked the seventh-largest in the world based on applicable 2021 revenues. ...

won the contract to replace the M198 in the US Army and Marine Corps with its

M777 The M777 howitzer is a British towed 155 mm artillery piece in the howitzer class. It is used by the ground forces of Australia, Canada, Colombia, India, Saudi Arabia, Ukraine, and the United States. It was first used in combat during the US ...

155 mm/39 cal towed howitzer, which weighs less than . It was introduced in 2005.

Operators

Current operators

* : 18 in service with the

Royal Bahraini Army Royal Bahraini Army is the ground force component of the Bahrain Defence Force. The army's current strength is 15,000 personnel and headed by Lieutenant General Khalifa bin Abdullah Al-Khalifa. History Bahraini ground troops took part in the Sa ...

* : Brazilian Army 120 units. * : 12 * : 12 * : 120 howitzers supplied by the United States. * : Total is 219 pieces. 36 howitzers operated by the LAF since the 1980s, 41 howitzers received in 2008, followed by 30 M-198 Howitzers in January 2010, 72 pieces delivered on February 8, 2015, and a batch of 40 pieces on September 8, 2016. * : 35 units. * : 184 in service with the

Pakistan Army The Pakistan Army (, ) is the Army, land service branch of the Pakistan Armed Forces. The roots of its modern existence trace back to the British Indian Army that ceased to exist following the partition of India, Partition of British India, wh ...

. * : 42 * : 18 in service * : 57–60 units in service. * : 116 units in service with

Royal Thai Army The Royal Thai Army or RTA ( th, กองทัพบกไทย; ) is the army of Thailand and the oldest and largest branch of the Royal Thai Armed Forces. History Origin The Royal Thai Army is responsible for protecting the kingdom's so ...

Former operators

* : 36 * : 52 captured. Some were taken back while other were destroyed by air strikes. * : 358

References

External links

{{Commons category, M198 howitzer
Weapon Profile
as part of ''The Whirlwind War The United States Army in Operations DESERT SHIELD and DESERT STORM'' a publication of the

United States Army Center of Military History The United States Army Center of Military History (CMH) is a directorate within the United States Army Training and Doctrine Command. The Institute of Heraldry remains within the Office of the Administrative Assistant to the Secretary of the Arm ...

www.fas.org – M198 Towed Howitzer

Development prototype XM198 (U.S. Army photo)
155 mm artillery Cold War artillery of the United States Field artillery Artillery of the United States United States Marine Corps equipment Howitzers Military equipment introduced in the 1970s