M101 howitzer

M101A1 105 mm Howitzer
U.S. Marines fire a M101A1 105 mm howitzer during a ceremony in 2005
Type Howitzer
Place of origin United States
Service history
Used by United States
Wars World War II
Korean War
First Indochina War
Vietnam War
Insurgency in the Philippines
Production history
Manufacturer Rock Island Arsenal
Produced 1941–1953
No. built 10,200
Weight 4,980 lb (2,260 kg)
Length 19 ft 6 in (5.94 m)
Barrel length 7 ft 7 in (2.31 m) L/22
Width 7 ft 3 in (2.21 m)
Height 5 ft 8 in (1.73 m)

Shell 105x372R
Caliber 105 mm (4.1 in)
Breech Horizontal-block
Recoil Hydro-pneumatic, constant, 42 in (110 cm)
Carriage split trail
Elevation -5° to +66°
Traverse 46°
Muzzle velocity 1,550 ft/s (472 m/s)
Maximum firing range 7.00 mi (11,270 m)

The 105 mm M101A1 howitzer (previously designated M2A1) was an artillery piece developed and used by the United States. It was the standard U.S. light field howitzer in World War II and saw action in both the European and Pacific theaters. Entering production in 1941, it quickly gained a reputation for accuracy and a powerful punch. The M101A1 fired 105 mm (4.1 in) high explosive (HE) semi-fixed ammunition and had a range of 12,330 yards (11,270 m), making it suitable for supporting infantry.

All of these qualities of the weapon, along with its widespread production, led to its adoption by many countries after the war. Its ammunition type also became the standard for many foreign countries' later models.


During the Second World War, U.S. artillery regiments consisted of an HQ detachment, one 155 mm artillery battalion, and three 105 mm artillery battalions. Both the 155 mm and 105 mm battalions had twelve guns each, divided into three batteries of four guns. That gave each regiment a total of twelve 155 mm howitzers, and thirty-six 105 mm howitzers.[1]

The U.S. military artillery designation system was changed in 1962, redesignating the 105 mm M2A1 howitzer the M101A1. The gun continued to see service in the Korean and Vietnam Wars. Though a similar model, the M102 howitzer, shared the same roles in battle, it never fully replaced the M101A1. Today, the M101A1 has been retired by the U.S. military, though it continues to see service with many other countries. By the end of the Second World War, 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.

The Canadian Forces continued to use the M2A1 as the C2 Howitzer until 1997 when a modification was made to extend its service life; it is now designated the C3. The changes include a longer barrel, a muzzle brake, reinforced trails and the removal of shield flaps. It remains the standard light howitzer of Canadian Forces Reserve units. The C3 is used by Reserve units in Glacier National Park in British Columbia as a means of avalanche control. In addition, the M101 has found a second use in the U.S. as an avalanche control gun, supervised by the US Forest Service 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 Two Medal of Honor recipient names on their barrels.[2]

France and the State of Vietnam used M2A1 howitzers during the First Indochina War, as did the Viet Minh guerilla forces, who were supplied with at least 24 by the People's Republic of China, along with other captured American artillery pieces and mortars formerly operated by the Nationalist Chinese forces (the Kuomintang military). 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 VPA). It continues to remain as the primary tactical field-howitzer of the VPA.[3][4]

A number of M2/M101 howitzers were used by the Socialist Federal Republic of Yugoslavia and approximately 50 were inherited by Croatia, of which four are still in use for training with the Croatian Army.

M2 Howitzers are still in limited service in the Australian Army Reserve, but are being replaced with 81-millimetre (3.2 in) mortars with an emphasis on the retention of indirect fire support skills.[5] In regular service they were replaced by the 105 mm L119 Hamel gun and the 155-millimetre (6.1 in) M198 howitzers.

Two M2 howitzers (1942) are still employed in providing the gun salute at Kristiansten Fortress, in Trondheim, Norway. M101/M2 is one of three approved salute guns in the Norwegian armed forces, and have been reduced to a caliber of 75 millimetres (3.0 in) for this purpose. They are used for gun salute also at Rena and Setermoen.


Gun variants:

  • M1920 - prototype.[6]
  • M1925E - prototype.[6]
  • T2 prototype, standardized as M1.[6]
  • M2 (1934) - minor changes to the chamber to allow use of fixed ammunition.[6]
  • M2A1 (1940) - modified breech ring.[7]
  • M3 - lightweight howitzer, with barrel shortened by 27 inches.
  • T8 prototype (standardized as 105 mm M4 Howitzer in September, 1943) - vehicle-mounted variant with modified breech and with cylindrical recoil surface.[8]:210
  • M101 - post-war designation of M2A1 on carriage M2A1
  • M101A1 - post-war designation of M2A1 on carriage M2A2
  • M2A1 modernized variant by Yugoimport SDPR with max range of 18.1kmm and 8rds per minute[9]
  • C3 - Canadian C1 (M2A1) with lengthened, 33-caliber barrel

Carriage variants:

  • M1920E - prototype, split trail.[6]
  • M1921E - prototype, box trail.[6]
  • M1925E - prototype, box trail.[6]
  • T2, standardized as M1 - split trail, wooden wheels.[6]
  • M1A1 - M1 carriages rebuilt with new wheels, brakes and other parts.[7]
  • T3 - prototype.[6]
  • T4 - prototype.[6]
  • T5, standardized as M2 (1940) - split trail, steel wheels with pneumatic tires.[6]
  • M2A1 - electric brakes removed.[10]
  • M2A2 - modified shield.[10]
  • 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 155mm Howitzer with similar configuration). The base XM124 provided two 20 horsepower, air-cooled engines, while the XM124E1 provided a single 20 horsepower 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 Museum.

Self-propelled mounts


The gun fired semi-fixed ammunition, with 105 mm Cartridge Case M14. The propelling charge consisted of a base charge and six increments, 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.[15]

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.[15]

Available ammunition[13]:236[15][16]
Type Model Weight, kg (round/projectile) Filler Muzzle velocity, m/s Range, m
HE HE M1 Shell 19.08 / 14.97 TNT or 50/50 amatol, 2.18 kg 472 11,160
HE-AT HE-AT M67 Shell 16.71 / 13.25 Pentolite, 1.33 kg 381 7,854
Smoke HC BE M84 Shell 19.02 / 14.91 Zinc chloride (HC) 472 11,160
Smoke, colored BE M84 Shell 17.86-18.04 / Smoke mixture
Smoke WP M60 Shell 19.85 / 15.56 White Phosphorus (WP), 1.84 kg 472 11,110
Smoke FS M60 Shell 20.09 / Sulfur trioxide in Chlorosulfonic acid, 2.09 kg
Chemical H M60 Shell 19.43 / Mustard gas, 1.44 kg
Practice Empty M1 Shell 472 11,160
Drill Drill Cartridge M14 - -
Blank - -
Armor penetration, mm[13]:236[17][18]
Ammunition \ Distance, m 0 457 914 1,828
HEAT M67 Shell (meet angle 0°) 102-183
Concrete penetration, mm[13]:236
HE M1 Shell (meet angle 0°) 457 427 396 335
Different methods of measurement were used in different countries / periods. Therefore, direct comparison is often impossible.


See also

  • List of U.S. Army weapons by supply catalog designation (SNL C-21)
  • [[List of U.S. Army munitions by supply catalog designation#Class R1Q (105 mm Howitzer; semi-fixed Ammunition for M2, M2A1, and M4 Howitzer)|List of U.S. Army munitions by supply catalog designation (semi-fixed Ammunition for 105 mm M2, M2A1, and M4 Howitzer)]] (AIC R1Q or R1U)
  • L118 Light Gun - Lightweight 105 mm howitzer designed in the 1970s
  • LG1 - Modern lightweight 105 mm howitzer
  • G7 - Modern 105 mm howitzer
  • M56 105 mm similar to the M101 made in ex Yugoslavia and still made in Serbia including new and old variant and Bosnia only old variant


  1. "Archived copy" (PDF). Archived (PDF) from the original on 2016-12-22. Retrieved 2016-09-22. McKenney, Janice E (2007). The Organizational History of Field Artillery, 1775–2003 (CMH Pub 60-16). Army Lineage Series. Washington: Center of Military History. pp 146.
  2. "428th Field Artillery Brigade | Fort Sill | Oklahoma | Fires Center of Excellence". sill-www.army.mil. Retrieved 2018-07-05.
  3. 1 2 "M2A1 105 mm light field howitzer on the way to base, after a live firing exercise". March 31, 2014. Archived from the original on May 11, 2018.
  4. 1 2 "M2A1 howitzer on the way to firing ground". March 25, 2014. Archived from the original on May 11, 2018.
  5. Toohill, MAJ Ian (August 2009). "Mortars for Reserve Gunners" (PDF). 2nd Division, Army Reserves Public Affairs. The Bayonet. p. 10. Archived from the original (PDF) on 27 February 2012. Retrieved 6 January 2012.
  6. 1 2 3 4 5 6 7 8 9 10 11 Hogg - Allied Artillery of World War Two, p 42-49.
  7. 1 2 Technical Manual TM 9-2005 volume 3, Infantry and Cavalry Accompanying Weapons.
  8. 1 2 3 4 Hunnicutt - Sherman: A History of the American Medium Tank
  9. "Archived copy" (PDF). Archived (PDF) from the original on 2018-04-05. Retrieved 2018-04-04.
  10. 1 2 Technical Manual TM 9-1325, 105 mm Howitzers M2 and M2A1; Carriages M2A1 and M2A2; and Combat Vehicle Mounts M3 and M4.
  11. Hunnicutt - Pershing: A History of the Medium Tank T20 Series
  12. 1 2 3 4 5 Hunnicutt - Stuart: A History of the American Light Tank
  13. 1 2 3 4 Hunnicutt - Half-Track: A History of American Semi-Tracked Vehicles
  14. "Vietnam Has Developed a 105mm Self-Propelled Howitzer on a Ural-375D Chassis 20051531 - May 2015 Global Defense Security news UK - Defense Security global news industry army 2015 - Archive News year". www.armyrecognition.com. Archived from the original on 2015-05-24.
  15. 1 2 3 Technical Manual TM 9-1901, Artillery Ammunition, p 167-178.
  16. Technical Manual TM 9-1904, Ammunition Inspection Guide, p 471-484.
  17. "Untitled Document" (PDF). www.90thidpg.us. Archived from the original (PDF) on 2016-03-15.
  18. "Archived copy" (PDF). Archived (PDF) from the original on 2017-05-17. Retrieved 2017-06-13.
  19. "Trade Registers". armstrade.sipri.org. Archived from the original on 2010-04-14.
  20. John Keegan, page 589 World Armies, ISBN 0-333-17236-1
  21. Engelbrecht, Leon. "Fact file: G6 L45 self-propelled towed gun-howitzer - defenceWeb". www.defenceweb.co.za. Archived from the original on 2014-01-09.


  • Hogg, Ian V. (1998). Allied Artillery of World War Two. Crowood Press, Ramsbury. ISBN 1-86126-165-9. 
  • Hunnicutt, R. P. (1971). Pershing: A History of the Medium Tank T20 Series. Feist Publications. 
  • Hunnicutt, R. P. (1992). Stuart: A History of the American Light Tank. Presidio Press. ISBN 0-89141-462-2. 
  • Hunnicutt, R. P. (1994). Sherman: A History of the American Medium Tank. Presidio Press. ISBN 0-89141-080-5. 
  • Hunnicutt, R. P. (2001). Half-Track: A History of American Semi-Tracked Vehicles. Presidio Press. ISBN 0-89141-742-7. 
  • Technical Manual TM 9-1325, 105 mm Howitzers M2 and M2A1; Carriages M2A1 and M2A2; and Combat Vehicle Mounts M3 and M4. War Department, 1944. 
  • Technical Manual TM 9-1901, Artillery Ammunition. War Department, 1944. 
  • Technical Manual TM 9-1904, Ammunition Inspection Guide. War Department, 1944. 
  • Technical Manual TM 9-2005 volume 3, Infantry and Cavalry Accompanying Weapons. War Department, 1942. 
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