The M101A1 (previously designated Howitzer M2A2 on Carriage M2A2) howitzer is an artillery piece developed and used by the United States. It was the standard U.S. light field howitzer in
World War II
World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...
Korean War
The Korean War (25 June 1950 – 27 July 1953) was an armed conflict on the Korean Peninsula fought between North Korea (Democratic People's Republic of Korea; DPRK) and South Korea (Republic of Korea; ROK) and their allies. North Korea was s ...
. Entering production in 1941, it quickly gained a reputation for accuracy and a powerful punch. The M101A1 fires 105 mm
high explosive
An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An exp ...
(HE) semi-fixed ammunition and has a range of or 7 miles, making it suitable for supporting
infantry
Infantry, or infantryman are a type of soldier who specialize in ground combat, typically fighting dismounted. Historically the term was used to describe foot soldiers, i.e. those who march and fight on foot. In modern usage, the term broadl ...
.
History
Development and designation
After World War I, the U.S. Army Ordnance Department studied various captured German 105 mm-caliber howitzers and developed the 105 mm Howitzer M1920 by using the Carriage M1920. A box trail carriage design (the M1925E carriage) and two other split trail designs (the T1 and T2) were also developed, but the original split trail design was found superior after testing. After being selected, the piece was standardized in December 1927, as the 105 mm howitzer M1 on carriage M1. The Army had an intention to replace all 75 mm gun-howitzers in its divisional and non-divisional field artillery regiments with 105 mm pieces, but a lack of appropriations stalled the idea and eventually forced it to be completely abandoned by 1929; a limited plan developed in 1925 envisioned re-equipping three regiments, but by 1933, only 14 M1 howitzers had been manufactured.
A modified version of the M1 was trialed in 1932 which used semi-fixed ammunition instead of separate-loading ammunition. Since this development required a different breech block, the new piece was designated the 105 mm howitzer M2 on carriage M1. 48 pieces were manufactured in 1939. The original M1 carriage had been designed for towing using horses rather than trucks, and a new carriage, the T5 (M2), was developed in 1939 and standardized in February 1940. The breech ring of the howitzer M2 was modified in March 1940 before large-scale production began, creating the 105 mm howitzer M2A1 on carriage M2.
In 1939, the new howitzer cost $25,000, which was three times more than a 75 mm field gun M1897 on M2 carriage, and its adoption required procurement of a colossal amount of new ammunition (War Department estimate of $26 million).
The gun was designed to be very durable and was therefore heavy for its caliber, but studies after 1943 found that after prolonged firing, the muzzle end of the barrel was prone to cracking. To relieve stress in the barrel, new production M2A1 tubes were counterbored two inches from the muzzle starting in the late 1940s. By the end of World War II, 8,536 105 mm towed howitzers had been built and post-war production continued at Rock Island Arsenal until 1953, by which time 10,202 had been built.
In 1953, the new howitzer M2A2 was standardized to further increase the life of the howitzer at the cost of some muzzle velocity. The M2A2's barrel had a higher strength breech ring, deeper rifling grooves, and shallower rifling taper than the M2A1's barrel, resulting in a 50 percent more effective full charge barrel life than the M2A1.
A further developed howitzer M2A2E2, featuring a muzzle brake and maximal range increased along with the propelling charge, on carriage M2A2E2, featuring an increased maximal angle of fire, were designed and tested in 1958, but with the coming XM102 howitzer both were canceled in 1961.
In November 1960, U.S. military artillery designation system began to change, where howitzer M2A1 or M2A2 on carriage M2A1 were renamed the M101 and howitzer M2A1 or M2A2 on carriage M2A2 were renamed the M101A1. This howitzer continued to see service through the
Vietnam War
The Vietnam War (1 November 1955 – 30 April 1975) was an armed conflict in Vietnam, Laos, and Cambodia fought between North Vietnam (Democratic Republic of Vietnam) and South Vietnam (Republic of Vietnam) and their allies. North Vietnam w ...
. Though the successor M102 howitzer was adopted in 1964, both M101 and M102 shared similar roles in battle and the M101A1 was never fully replaced in front-line service until the adoption of the M119 howitzer. Today, the M101A1 has been retired by the U.S. military, though it continues to see service with many other countries.
Australia
The M2A2 howitzer was retired from regular service with the
Australian Army
The Australian Army is the principal Army, land warfare force of Australia. It is a part of the Australian Defence Force (ADF), along with the Royal Australian Navy and the Royal Australian Air Force. The Army is commanded by the Chief of Army ...
in 1988, when it was replaced by the 105 mm L118 and L119, which in turn were replaced by the M777A2 in 2014. The M2A2 remained in service with the
Australian Army Reserve
The Australian Army Reserve is a collective name given to the military reserve force, reserve units of the Australian Army. Since the Federation of Australia in 1901, the reserve military force has been known by many names, including the Citize ...
until its replacement by mortars in the late 2000s. Australia's Federation Guard retains six pieces for ceremonial use.
Canada
The
Canadian Forces
The Canadian Armed Forces (CAF; , FAC) are the unified Military, military forces of Canada, including sea, land, and air commands referred to as the Royal Canadian Navy, Canadian Army and the Royal Canadian Air Force. Under the ''National Defenc ...
procured at least 60 US made M2A1 howitzers, beginning in 1952, and also had Sorel Industries of Canada produce 232 of a slightly modified M2A2 version, starting in 1955. The Canadian produced guns were later designated C1, while the US produced guns were designated C2. These continued in service until the early 2000s. In the late 1990s, ninety-six C1 guns were selected and sent to RDM in the Netherlands to extend their service life. These guns were re-designated as the C3. The changes include a longer 33-calibre barrel, a
muzzle brake
A muzzle brake or recoil compensator is a device connected to, or a feature integral (ported barrel) 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 re ...
, reinforced trails and the removal of shield flaps. It remains the standard light howitzer of Canadian Forces Reserve units. The C3 is used by 1RCHA in Glacier National Park in
British Columbia
British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...
as a means of
avalanche
An avalanche is a rapid flow of snow down a Grade (slope), slope, such as a hill or mountain. Avalanches can be triggered spontaneously, by factors such as increased precipitation or snowpack weakening, or by external means such as humans, othe ...
control. The C3 is used to train Regular Force Artillery in Shilo MB. The modified 105mm C3 howitzer has a range of 18km.
Croatia
A number of M2/M101 howitzers were used by the
Socialist Federal Republic of Yugoslavia
The Socialist Federal Republic of Yugoslavia (commonly abbreviated as SFRY or SFR Yugoslavia), known from 1945 to 1963 as the Federal People's Republic of Yugoslavia, commonly referred to as Socialist Yugoslavia or simply Yugoslavia, was a country ...
and approximately 50 were inherited by
Croatia
Croatia, officially the Republic of Croatia, is a country in Central Europe, Central and Southeast Europe, on the coast of the Adriatic Sea. It borders Slovenia to the northwest, Hungary to the northeast, Serbia to the east, Bosnia and Herze ...
, of which four are still in use for training with the
Croatian Army
The Croatian Army ( or HKoV) is the land force branch of the Croatian Armed Forces. It is numerically the largest of the three branches of the Croatian Armed Forces. The HKoV is the main force for the defense of the country against external threa ...
.
France
The French Army used the M2 howitzer, designated ''HM2'', during World War II, in the
Algerian War
The Algerian War (also known as the Algerian Revolution or the Algerian War of Independence) ''; '' (and sometimes in Algeria as the ''War of 1 November'') was an armed conflict between France and the Algerian National Liberation Front (Algeri ...
Chad
Chad, officially the Republic of Chad, is a landlocked country at the crossroads of North Africa, North and Central Africa. It is bordered by Libya to Chad–Libya border, the north, Sudan to Chad–Sudan border, the east, the Central Afric ...
Rwandan Civil War
The Rwandan Civil War was a large-scale civil war in Rwanda which was fought between the Rwandan Armed Forces, representing the country's government, and the rebel Rwandan Patriotic Front (RPF) from 1October 1990 to 18 July 1994. The war arose ...
that led into the
Rwandan genocide
The Rwandan genocide, also known as the genocide against the Tutsi, occurred from 7 April to 19 July 1994 during the Rwandan Civil War. Over a span of around 100 days, members of the Tutsi ethnic group, as well as some moderate Hutu and Gre ...
.
Germany
The
German Army
The German Army (, 'army') is the land component of the armed forces of Federal Republic of Germany, Germany. The present-day German Army was founded in 1955 as part of the newly formed West German together with the German Navy, ''Marine'' (G ...
adopted the M101 howitzer in a modified form in March 1956, designated Feldhaubitze 105 mm M1A2 (Bw). Using components made by
Rheinmetall
Rheinmetall AG () is a German automotive and arms manufacturer, headquartered in Düsseldorf, Germany. The group was promoted to the DAX, Germany's leading stock market index, in March 2023. It is the largest German and fifth largest Europe ...
, the new howitzers had a longer, un-counterbored 27-caliber barrel, a large single-baffle muzzle brake, and a larger gun shield.
Philippines
M2A1 howitzers were used by the PEFTOK. By the 1980s these wartime artillery pieces were replaced by M101s, and were used against the NPA and the MNLF, and the MILF. Several M101 howitzers are still in use with the
Armed Forces of the Philippines
The Armed Forces of the Philippines (AFP) () are the military forces of the Philippines. It consists of three main service branches; the Philippine Army, Army, the Philippine Air Force, Air Force, and the Philippine Navy, Navy (including the P ...
and are normally used to battle rebels in Luzon, Visayas, and Mindanao. They were also used in direct fire against Islamic militants during the
Battle of Marawi
The siege of Marawi (), also known as the Marawi crisis () and the Battle of Marawi (), was a five-month-long armed conflict in Marawi, Philippines, that started on May 23, 2017, between Government of the Philippines, Philippine government Arme ...
.
South Korea
Starting on 6 July 1950, South Korea received a total of 1,127 M2A1s until the end of the
Korean War
The Korean War (25 June 1950 – 27 July 1953) was an armed conflict on the Korean Peninsula fought between North Korea (Democratic People's Republic of Korea; DPRK) and South Korea (Republic of Korea; ROK) and their allies. North Korea was s ...
to supplement and replace the M1 75 mm howitzer and the M3 105 mm howitzer.
In the early 1970s, the ROK Armed Forces needed to replace these old howitzers due to the maintenance burden. To match North Korea's artillery capability, South Korea invested in the domestic arms industry to equip its large military cost efficiently. After completion of ''Project Thunder I'', supported by the U.S. Department of Defense, for infantry weapons, in April 1972, the South Korean president
Park Chung Hee
Park Chung Hee (; ; November14, 1917October26, 1979) was a South Korean politician and army officer who served as the third president of South Korea from 1962 after he seized power in the May 16 coup of 1961 until Assassination of Park Chung ...
ordered ''Project Thunder II'' for artillery weapons. The U.S. refused to cooperate due to the then diplomatic overtures to the
People's Republic of China
China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...
. The U.S. Embassy in South Korea ordered its technical team to withdraw, believing that South Korea lacked the tooling and knowledge to develop the weapons by itself. The
Agency for Defense Development
The Agency for Defense Development (ADD, ) is the South Korean government agency for research and development in defense technology, funded by the Defense Acquisition Program Administration (DAPA). It was established in August 1970 under the ban ...
however, reverse engineered the M2A1 (M101A1), and prototype production began in March 1973.
On 25 June 1973, three prototypes were demonstrated publicly. After the test, the U.S. ambassador Philip Habib arranged the meeting of South Korean chief secretary O Won-cheol and colonel Montgomery from the Joint U.S. Military Affairs Group-Korea. The colonel provided technical review of the howitzer, and recommended purchasing of the U.S. equipment for logistics issues because the howitzer was not compatible with the U.S. standard. South Korea refused and pursued domestic design, but the two nations eventually signed an agreement for technology transfer in September 1973. It was the first weapons research cooperation between the two nations, and the South Korean defense industry began to form with guidance from the U.S.
In February 1974, hostilities grew after North Korea sunk a South Korean fishing boat and kidnapped fishermen near Baengnyeong Island. As a response, 10 howitzers crafted prior to the research cooperation were sent to the island, but pulled out after having severe malfunctions during operations. In November 1975, the reinforced variant experienced barrel breakdown; the failure led to the invitation of American engineers in January 1976 for an overview. After 1.5 months of inspection, the engineers suggested the
Eighth United States Army
The Eighth Army is a U.S. field army which commands all United States Army forces in South Korea. It is headquartered at the Camp Humphreys in the Anjeong-ri of Pyeongtaek, Pyeongtaek, South Korea.Hyundai Wia) in
Changwon
Changwon (; ) is the capital and largest city of South Gyeongsang Province, South Korea (with a population of 1,025,702 ), and the 11th largest city of the South Korea, country. A port city, Changwon is bordered by Masan Bay to the south, and the ...
.
In 1978, South Korea restarted domestic howitzer program based on M101A1. The howitzer applied 38 calibers barrel for extending the maximum range to 18 km using RAP ammunition. Only 18 howitzers saw service with South Korean military in favor of mass-producing KH179 155 mm towed howitzer.
As of 2021, South Korea is the largest operator of the M101 howitzer with about 2,000 pieces in active service. It is planned to convert 1/3 of its inventory to K105A1 self-propelled howitzer.
Vietnam
France
France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...
First Indochina War
The First Indochina War (generally known as the Indochina War in France, and as the Anti-French Resistance War in Vietnam, and alternatively internationally as the French-Indochina War) was fought between French Fourth Republic, France and Việ ...
, as did the
Viet Minh
The Việt Minh (, ) is the common and abbreviated name of the League for Independence of Vietnam ( or , ; ), which was a Communist Party of Vietnam, communist-led national independence coalition formed at Pác Bó by Hồ Chí Minh on 19 May 1 ...
guerilla forces they fought against, who were supplied with at least 24 by the
People's Republic of China
China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...
, along with other captured American artillery pieces and mortars formerly operated by both Nationalist Chinese forces (the
Kuomintang
The Kuomintang (KMT) is a major political party in the Republic of China (Taiwan). It was the one party state, sole ruling party of the country Republic of China (1912-1949), during its rule from 1927 to 1949 in Mainland China until Retreat ...
military) and US troops fighting in Korea. Today upgraded M2A1 howitzers (some of which have been mounted on trucks and employed as self-propelled artillery) are still being used by the
People's Army of Vietnam
The People's Army of Vietnam (PAVN), officially the Vietnam People's Army (VPA; , , ), also recognized as the Vietnamese Army (), the People's Army () or colloquially the Troops ( ), is the national Military, military force of the Vietnam, S ...
(the PAVN).
Other uses
In addition, the M101 has found a second use in the U.S. as an avalanche control gun, supervised by the
US Forest Service
The United States Forest Service (USFS) is an agency within the U.S. Department of Agriculture. It administers the nation's 154 national forests and 20 national grasslands covering of land. The major divisions of the agency are the Chief's ...
and the US Army TACOM's cooperative effort in the Avalanche Artillery Users of North America Committee (AAUNAC). The M101 is used by a number of ski areas and state departments of transportation for long-range control work. Under the designation of M2A2, the 2nd Battalion, 2nd Field Artillery Regiment, 428th Field Artillery Brigade performs salutes with 7 guns with World War II Medal of Honor recipient names on their barrels.
Variants
Gun variants:
* M1920 – prototype.Hogg – ''Allied Artillery of World War Two'', p 42–49.
* M1925E – prototype.
* T2 – prototype, standardized as M1.
* M2 (1934) – minor changes to the chamber to allow the use of fixed ammunition.
* M2A1 (1940) – modified breech ring.''Technical Manual TM 9-2005 volume 3, Infantry and Cavalry Accompanying Weapons''.
* M2A2 (1953) – deeper rifling and shorter rifling taper.
* M2A2E2 (1958) – prototype with muzzle brake.
* M3 – lightweight howitzer, with barrel shortened by with carriage of the M1 pack howitzer.
* T8 – prototype vehicle-mounted variant with modified breech and with cylindrical recoil surface, standardized as 105 mm M4 howitzer in September, 1943.
* FH M1A2 – Rheinmetall-modified M101 in German service.
* M101 – post-1961 designation of M2A1 or M2A2 on carriage M2A1.
* M101A1 – post-1961 designation of M2A1 or M2A2 on carriage M2A2.
* M2A1 – modernized L33 variant by Yugoimport SDPR with max range of / (boat tail shell/base bleed shell)
* C3 – Canadian C1 (M2A1) with lengthened, 33-caliber barrel
* KM101A1 – South Korean license of M101A1, 1977
* KH178 – South Korean 38 calibers variant, 1983
Carriage variants:
* M1920E – prototype,
split trail
A gun carriage is a frame or a mount that supports the gun barrel of an artillery piece, allowing it to be maneuvered and fired. These platforms often had wheels so that the artillery pieces could be moved more easily. Gun carriages are also use ...
.
* M1921E – prototype, box trail.
* M1925E – prototype, box trail.
* T2, standardized as M1 – split trail, wooden wheels.
* M1A1 – M1 carriages rebuilt with new wheels, brakes and other parts.
* T3 – prototype.
* T4 – prototype.
* T5, standardized as M2 (1940) – split trail, steel wheels with pneumatic tires.
* M2A1 – electric brakes removed.''Technical Manual TM 9-1325, 105 mm Howitzers M2 and M2A1; Carriages M2A1 and M2A2; and Combat Vehicle Mounts M3 and M4''.
* M2A2 – modified shield.
* M2A2E2 – prototype with increased elevation to 70 degrees.
* XM124 & XM124E1 light auxiliary propelled howitzer – prototype (1962–1965) – produced by Sundstrand Aviation Corporation, who added an auxiliary drive system for local maneuverability (See also similar XM123 Medium Auxiliary Propelled 155 mm Howitzer with similar configuration). The base XM124 provided two , air-cooled engines, while the XM124E1 provided a single engine and electric steering.
* M2A2 Terra Star auxiliary propelled howitzer – prototype (1969–1977) – Lockheed Aircraft Service Company added an auxiliary drive system and a tri-star wheel system to the carriage of an M2A2 105 mm light howitzer to provide local maneuverability. The last surviving example is at the
Rock Island Arsenal
The Rock Island Arsenal comprises 946 acres (383 ha) and is located on Arsenal Island, originally known as Rock Island, on the Mississippi River between the cities of Davenport, Iowa, and Rock Island, Illinois. It is home to the United Stat ...
Museum.
File:Canadian C3 howitzer March 3, 2009.jpg, Canadian soldiers fire a high explosive round with a C3 howitzer in 2009.
File:Royal Thai army M101.jpg, Royal Thai army M101 with new barrel.
File:XM124E2 Light Auxiliary-Propelled 105mm Howitzer.jpg, XM124E2 light auxiliary-propelled 105 mm howitzer at the
Rock Island Arsenal
The Rock Island Arsenal comprises 946 acres (383 ha) and is located on Arsenal Island, originally known as Rock Island, on the Mississippi River between the cities of Davenport, Iowa, and Rock Island, Illinois. It is home to the United Stat ...
museum
File:M2A2 Terra Star 105mm Auxiliary Propelled Howitzer front quarter.jpg, The only surviving prototype M2A2 Terra Star auxiliary propelled howitzer at the
Rock Island Arsenal
The Rock Island Arsenal comprises 946 acres (383 ha) and is located on Arsenal Island, originally known as Rock Island, on the Mississippi River between the cities of Davenport, Iowa, and Rock Island, Illinois. It is home to the United Stat ...
Republic of Korea Army
The Republic of Korea Army (ROKA; ), also known as the ROK Army or South Korean Army, is the army of South Korea, responsible for ground-based warfare. It is the largest of the military branches of the Republic of Korea Armed Forces with 365,0 ...
(initially called EVO-105)
* Vietnamese M101 howitzer mounted on an Ural-375D 6×6 truck.
Ammunition
The gun fired semi-fixed ammunition, with 105 mm Cartridge Case M14. The propelling charge consisted of a base charge and six incremental charges, forming seven charges from 1 (the smallest) to 7 (the largest). Use of M1 HE rounds prepared for the 105 mm howitzer M3 (same projectile and cartridge, but different propelling charge) was authorized.''Technical Manual TM 9-1901, Artillery Ammunition'', p 167–178.
HEAT M67 Shell was originally designed as fixed round, with Cartridge Case M14 type II. It was later changed to semi-fixed type with the standard cartridge, but with non-adjustable propelling charge. For blank ammunition, a shorter Cartridge Case M15 with black powder charge was used.
Operators
*
*
* : ''Haubitze M1A2''
*
* ''M101A1'' variant. 50 delivered in 1982. Status uncertain.
*
*
*
*
*
*
*
*
* Designated C3 - 93 in service
*
*
*
*
*
*
*
*
*
*
*
*
*
* (Salute gun)
*
*
*
*
*
*
* in service between 1950 ed il 1976
* operated by 2000. A small number were produced domestically as Type 58. Some M2A1s remain in service for ceremonial purpose.
*
*
*
*
*
* – 54 acquired from Denmark in 2002. At least 18 units were donated to Ukraine in 2022.
*
*
*
*
*
*
*
* – 242 in service
*
*
*
*
*
*
*
*
*
* John Keegan, page 589 ''World Armies'',
*
*
*
*
*
*
* (Avalanche control)
*
*
*
*
*
* (Avalanche control and Salute gun)
*
*
*
**
*
See also
*
List of U.S. Army weapons by supply catalog designation
This is a historic (index) list of United States Army weapons and materiel, by their Standard Nomenclature List (SNL) group and individual designations — an alpha-numeric nomenclature system used in the United States Army Ordnance Corps Suppl ...
(SNL C-21)
* M3 howitzer – Shortened barrel variant of M2 howitzer.
* M102 howitzer – The US partial replacement for M101 howitzer.
* KH178 105 mm towed howitzer – South Korean 38 calibers variant of M101A1.
* Indian Field Gun – Indian 105 mm howitzer.
* L118 light gun – British 105 mm howitzer.
* M119 howitzer – The US license of L118, replacement for M101 and M102 howitzer.
* GIAT LG1 – French 105 mm howitzer.