M252 mortar

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British-designed medium weight mortar

title: "M252 mortar" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["81mm-mortars", "infantry-mortars", "mortars-of-the-united-states", "united-states-marine-corps-equipment", "military-equipment-introduced-in-the-1980s"] description: "British-designed medium weight mortar" topic_path: "geography/united-states" source: "https://en.wikipedia.org/wiki/M252_mortar" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary British-designed medium weight mortar ::

::data[format=table title="Infobox weapon"]

FieldValue
nameM252
imageFile:USMC-090504-M-1012C-001.jpg
captionM252 mortar
originUnited Kingdom (designed)
United States (manufactured)
typeMortar
is_ranged
is_artilleryyes
is_vehicle
service1987–present (United States)
used_bySee Operators
warsVietnam War (prototype model)
Soviet–Afghan War
Gulf War
War in Afghanistan
Iraq War
Syrian Civil War
variants
weight41.3 kg
part_length1.27 m
crew5
caliber81 mm
rate8–16 rpm sustained
20–30 rpm in exceptional circumstances and for short periods
rangeHE: 91–5,935 m
(99–6,490.6 yd)
feedmuzzle-loaded
sights
elevation45°–85.2°
traverse5.6°
::

| name = M252 | image = File:USMC-090504-M-1012C-001.jpg | caption = M252 mortar | origin = United Kingdom (designed) United States (manufactured) | type = Mortar | is_ranged = yes | is_bladed = | is_explosive = | is_artillery = yes | is_vehicle = | service = 1987–present (United States) | used_by = See Operators | wars = Vietnam War (prototype model) Soviet–Afghan War Gulf War War in Afghanistan Iraq War Syrian Civil War | designer = | design_date = | manufacturer = | production_date = | number = | variants = | weight = 41.3 kg | part_length = 1.27 m | crew = 5 | cartridge = | caliber = 81 mm | action = | rate = 8–16 rpm sustained 20–30 rpm in exceptional circumstances and for short periods | velocity = | range = HE: 91–5,935 m (99–6,490.6 yd) | max_range = | feed = muzzle-loaded | sights = | breech = | recoil = | carriage = | elevation = 45°–85.2° | traverse = 5.6°

The M252 81 mm medium weight mortar is a British-designed smooth bore, muzzle-loading, high-angle-of-fire weapon used for long-range indirect fire support to light infantry, air assault, and airborne units across the entire front of a battalion zone of influence. In the U.S. Army and U.S. Marine Corps, it is normally deployed in the mortar platoon of an infantry battalion.

Design

::figure[src="https://upload.wikimedia.org/wikipedia/commons/0/01/151024-M-CJ278-001_(22698262229).jpg" caption="Mortar team carrying (L-R) the mount, the baseplate and sight, and the cannon for an M252A2 system"] ::

The M252 system weighs 91 lb completely assembled and is composed of the M253 Cannon (35 lb), M177 Mount (27 lb), M3A1 Baseplate (29 lb), and the M64A1 Sight Unit (2.5 lb). The mount consists of a base plate and a bipod, which is provided with screw type elevating and traversing mechanisms to elevate/traverse the mortar. The M64A1 sight unit (also used on the M224) is attached to the bipod mount. The M252 is a gravity-fired smoothbore system. Attached to the muzzle of the weapon is the Blast Attenuation Device (BAD), used to reduce the blast effects on the mortar crew. To increase cooling efficiency, the breech end is finned; though first-hand accounts attest that the level of cooling is negligible. The cannon also has a crew-removable breech plug and firing pin.

High explosive rounds fired by the M252 weigh 10 lb with 0.7 kg of explosive filler and can have an effective kill radius of 115 ft.

In 2017, the Marines revealed they were developing precision-guided rounds for the 81 mm mortar, similar to efforts for the 120 mm Expeditionary Fire Support System but in a man-portable system.

History

The M252 is an adaptation of the British 81mm L16A2 mortar developed in the 1950s. It entered service with the U.S. Army and replaced the previous 81 mm M29 mortar in 1987. It was adopted due to the extended range (4,500 to) and enhanced lethality. In the U.S. it is produced by Watervliet Arsenal.

::figure[src="https://upload.wikimedia.org/wikipedia/commons/5/5f/US_Marines_get_hands_on_with_new_mortar_system_151024-M-CJ278-002.jpg" caption="Lighter, M252A2 version"] ::

A lightweight version, the M252A1 was first fielded in December 2014. By using lightweight materials such as aluminum, titanium and nylon kevlar the total weight was reduced by 12 lb to 79 lb. The M252A1 also required less maintenance with its grease-less internal gears. The M252A1 was scheduled to replace the M252 in 2016. In November 2016, the Watervliet Arsenal received a contract to produce the bipods which have an A-shaped bipod frame with deliveries to be completed by March 2020. As part of the same program, a lightweight version of the M224 60mm mortar the M224A1 was also developed. The Marines developed an improved M252A2 version that weighs about 8.16 kg less than the original and incorporates a 4× magnification sight with a new cooling system.

Operation

Crew

A crew of five enlisted personnel operate the M252: the squad leader, the gunner, the assistant gunner, the first ammunition bearer, and the second ammunition bearer.

  1. The squad leader stands directly behind the mortar where they can command and control their squad. In addition to having general oversight of all squad activities, they also supervise the emplacement, laying, and firing of the weapon.
  2. The gunner stands to the left of the mortar where they can manipulate the sight, traversing handwheel, and elevating handwheel. They place firing data on the sight and lays the mortar for deflection and elevation. They make large deflection shifts by shifting the bipod assembly and keep the bubbles level during firing.
  3. The assistant gunner stands to the right of the mortar, facing the barrel and ready to load. In addition to loading, they swab the bore after 10 rounds have been fired or after each fire mission. The assistant gunner is the person who actually fires the weapon.
  4. The first ammunition bearer stands to the right rear of the mortar. They have the duty of preparing the ammunition (charge settings, fuzes, etc...) and passing it to the assistant gunner.
  5. The second ammunition bearer stands to the right rear of the mortar behind the first ammunition bearer. They maintain and keep a record of the ammunition in addition to the data corresponding to each fire mission. Their twofold records include a written table of firing data, type, and number of rounds fired, and the safety pins pulled from each round to provide physical evidence to the accuracy of the table. In addition they provide local security for the mortar position.

File:Flickr - The U.S. Army - Securing Barge Matal.jpg|M252 mortar and crew in Afghanistan, 2009 File:Defense.gov News Photo 081026-M-8774P-089.jpg|M252 mortar crew and ammunition in Afghanistan, 2008 File:24 MEU Deployment 2012, 81 mm mortars live fire 120731-M-KU932-058.jpg|Marines fire an M-252 81mm mortar during live-fire training at Udairi Range in Kuwait, 2012 File:US Marines Euphrates River Valley in Deir Ezzor province, Syria, Oct. 11, 2018.jpg|Marine M252 mortar crew deploying on a cliff-side in the Middle Euphrates River Valley in Syria, 11 October 2018

Types of rounds

::figure[src="https://upload.wikimedia.org/wikipedia/commons/5/53/81mm_mortar_rounds.png" caption="Three 81mm M29 Mortar rounds, M374A2 (High Explosive), M375A2 (White Phosphorus), and M301A3 (Illumination)."] ::

::figure[src="https://upload.wikimedia.org/wikipedia/commons/2/2d/M252A1_Ammo.jpg" caption="81mm ammunition for M252"] ::

While the M252 does fire a weapon-specific series of ammunition, it can also fire rounds from the M29 Mortar (only at charge 3 or below though). The M252 Mortar can fire the following principal classifications of training and service ammunition:

  • High explosive (HE): Designations M821, M821A1, M889, M889A1, M372-series, and M362. Used against personnel and light materiel targets.
    • M821A4 HE–Enhanced Fragmentation (HE–EF): is designed to satisfy insensitive munition requirements while enhancing lethality, which is achieved by utilizing preformed tungsten fragments.
    • Advanced Capability Extended Range Mortar (ACERM): Developmental guided round that adds wings, control fins, GPS navigation, a laser seeker, and an enhanced warhead; increases accuracy to within one meter and can reach a range of 20 km in five minutes. ACERM variations include a 120mm version with 24 to range, an 81mm extreme performance configuration with a 40 to range, a 5 inch naval gun configuration, including other gun systems, and an air dropped glide bomb version for delivery within a six times the altitude radius.
  • Smoke Cartridge: Designations M819 and M375-series. Used as a screening, signaling, or marking munition.
  • Illumination (ILLUM)
    • VIS ILLUM. Designations M853A1 and M301-series. Used in night missions requiring illumination for assistance in observation.
    • IR ILLUM. Designation M816. Provides an aerial parachuting Infrared Illuminating round for use with Infrared Night Vision Equipment.
    • Non-Lethal Indirect Fire Munition: Developmental round based on the M853A1 that disperses flash bang submunitions to temporarily daze people.
  • Practice (PRAC): Designations M880, M879, M68, and sabot. Used for training in limited areas.
  • Infrared Illumination (IR): Produces illumination which is only visible through the use of night vision devices.

Fuzes

The M252 rounds have three fuze types: the Multi-option Fuze (MOF) M734, the Mechanical Time & Super Quick (MTSQ) M772 and the Point-Detonating (PD) Fuze M935. The M734 is used for the M720 HE round and can be set to function as proximity burst, near-surface burst, impact burst, or delay burst, the M772 is used for the IR & VIS ILLUM (M816, M853A1) to activate the Illum candle during the rounds height point of its trajectory; the elevation and charge will determine the time set on the fuze.

Method of propulsion

::figure[src="https://upload.wikimedia.org/wikipedia/commons/2/29/USMC-110818-M-KU932-174.jpg" caption="Round with the standard four horseshoe charges"] ::

The range of a mortar is controlled by the number of propellant charges attached to the tail of the mortar designated M223. A charge is a semi-circular donut of nitrocellulose, which resembles a "horseshoe". A round for the M252 mortar comes with four charges attached. Longer-range shots require more propellant than can fit in the tail of the round, hence the necessity of external charges.

When the target is ranged, a mortar team member adjusts the amount of propellant by removing horseshoe charges from the projectile. The mortar squad leader verifies the number of charges; then the assistant gunner drops the round down the muzzle of the tube. The round, pulled by gravity, accelerates down the smooth bore of the mortar until the primer (in the base of the tail boom of the round) strikes the firing pin located in the bottom of the mortar tail assembly. The primer detonates, igniting the charge in the tail fin, which in turn ignites the horseshoes charges on the round. The charges deflagrate, releasing hot, expanding gas which pushes against the round with the obturating ring on the projectile, sealing the gas behind the projectile. The pressure from the expanding gas accelerates the projectile until it leaves the end of the tube.

Operators

::figure[src="https://upload.wikimedia.org/wikipedia/commons/0/02/M252_operators_2024.png" caption="Map with M252 operators in blue."] ::

Current operators

  • Australia: M252A1
  • Estonia
  • Iraq
  • Jordan
  • United States
    • 990 M252 as of January 2025

References

Soldiers with the Jordan Armed Forces’ 10th Border Guard Force, alongside their U.S. Army counterparts from the California National Guard’s 1st Squadron, 18th Cavalry Regiment, hangs an 81mm mortar round during the Jordan Operational Engagement Program with the M252 81 mm mortar system on Feb. 13, 2019 outside of Amman, Jordan.

References

  1. "Fact File: M252A1 Mortar".
  2. Hambling, David. (2 June 2016). "The Marines' Trusty Mortar Is Getting a Major Upgrade".
  3. {{usurped
  4. (11 December 2014). "Picatinny lightens Soldiers' load, shaves 12 pounds off mortar system". Picatinny Public Affairs.
  5. "U.S. Army Weapon Systems Handbook 2018".
  6. (29 November 2016). "Army awards $8.5M contract to Watervliet Arsenal to lighten the load for infantrymen, Marines". Watervliet Arsenal Public Affairs.
  7. Baddeley, Adam. (June 2011). "Mortars and Ammo".
  8. Schehl, Matthew L.. (7 December 2015). "Marines get new mortar in Iraq to protect base from IS".
  9. (10 May 2006). "81mm Mortar Ammunition And Fuzes".
  10. (29 April 2025). "Armaments & Ammunition 2025". U.S. Army.
  11. [https://www.military.com/kitup/2018/04/18/marines-hunt-mortar-round-can-fire-12-miles.html Marines In the Hunt for a Mortar Round That Can Fire Up to 12 Miles] {{Webarchive. link. (22 April 2018 . ''Military.com/Kitup''. 18 April 2018.)
  12. "Advanced Capability Extended Range Mortar (ACERM) - 2016 NDIA Armament Systems Forum".
  13. Pike, John. "M819 81mm Smoke Cartridge".
  14. "M816 81mm Infrared (IR) Illuminating Cartridge / M853A1 81mm Illuminating Cartridges".
  15. Sanborn, James K.. (6 December 2014). "Marines, soldiers could soon carry 'flash bang' mortars".
  16. Sanborn, James K.. (24 December 2014). "Need to know, 2015: What's new in gear and uniforms".
  17. "M772 & M776 Mechanical Time Super Quick (MTSQ) Fuze".
  18. (2017-03-17). "MORTARS Training Circular 3-22.90". HEADQUARTERS, DEPARTMENT OF THE ARMY.
  19. "FIELD MANUAL 23-90; TECHNICAL ORDER 11W2-5-13-21 - MORTARS". HEADQUARTERS DEPARTMENTS OF THE ARMY AND THE AIR FORCE.
  20. Dillon, Louis. (15 July 2019). "Army prepares for rollout of new handheld mortar computers". Defence Connect.
  21. (5 January 2017). "Iraq: Turning a blind eye: The arming of the Popular Mobilization Units". [[Amnesty International]].
  22. Military & Defense. "Peshmerga Military Equipment". Business Insider.
  23. (2025). "The Military Balance". [[International Institute for Strategic Studies]].
  24. "190213-A-GL488-519 {{!}} Soldiers with the Jordan Armed Forces' … {{!}} Flickr".

::callout[type=info title="Wikipedia Source"] This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page. ::

81mm-mortarsinfantry-mortarsmortars-of-the-united-statesunited-states-marine-corps-equipmentmilitary-equipment-introduced-in-the-1980s