M252 Mortar
Encyclopedia
The M252 81 mm medium weight mortar
is an American
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
.
and a base plate 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 smooth bore
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
.
developed in the 1950s. It entered service with the U.S. Army and replaced the previous 81 mm M29 mortar
in 1986. It was adopted due to the extended range (from 4,500 meters
to 5,650 meters) and enhanced lethality In the U.S. it is produced by Watervliet Arsenal
.
A much lighter version, the M252A1 was fielded for the first time in 2011. By reducing the number of parts and using lightweight materials, the total weight was reduced by 20.8 pounds. In the next several years, all U.S. Army M252s will be replaced by the M252A1. As part of the same program, a lighweight version of the M224 mortar
was developed.
The M252 uses a crew of five enlisted personnel to operate: the squad leader, the gunner, the assistant gunner, the first ammunition bearer, and the second ammunition bearer.
(only at charge 3 or below though). The M252 Mortar can fire the following principal classifications of training and service ammunition
.
types: the Multioption Fuze (M734
) and the Point-Detonating 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.
Mortar (weapon)
A mortar is an indirect fire weapon that fires explosive projectiles known as bombs at low velocities, short ranges, and high-arcing ballistic trajectories. It is typically muzzle-loading and has a barrel length less than 15 times its caliber....
is an American
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
smooth bore
Smoothbore
A smoothbore weapon is one which has a barrel without rifling. Smoothbores range from handheld firearms to powerful tank guns and large artillery mortars.-History of firearms and rifling:...
, muzzle-loading
Muzzleloader
A muzzleloader is any firearm into which the projectile and usually the propellant charge is loaded from the muzzle of the gun . This is distinct from the more popular modern designs of breech-loading firearms...
, high-angle-of-fire weapon
Weapon
A weapon, arm, or armament is a tool or instrument used with the aim of causing damage or harm to living beings or artificial structures or systems...
used for long-range indirect
Indirect fire
Indirect fire means aiming and firing a projectile in a high trajectory without relying on a direct line of sight between the gun and its target, as in the case of direct fire...
fire support
Fire support
Fire support is long-range firepower provided to a front-line military unit. Typically, fire support is provided by artillery or close air support , and is used to shape the battlefield or, more optimistically, define the battle...
to light infantry
Light infantry
Traditionally light infantry were soldiers whose job was to provide a skirmishing screen ahead of the main body of infantry, harassing and delaying the enemy advance. Light infantry was distinct from medium, heavy or line infantry. Heavy infantry were dedicated primarily to fighting in tight...
, air assault
Air assault
Air assault is the movement of ground-based military forces by vertical take-off and landing aircraft—such as the helicopter—to seize and hold key terrain which has not been fully secured, and to directly engage enemy forces...
, and airborne
Airborne forces
Airborne forces are military units, usually light infantry, set up to be moved by aircraft and 'dropped' into battle. Thus they can be placed behind enemy lines, and have an ability to deploy almost anywhere with little warning...
units across the entire front of a battalion
Battalion
A battalion is a military unit of around 300–1,200 soldiers usually consisting of between two and seven companies and typically commanded by either a Lieutenant Colonel or a Colonel...
zone of influence. In the U.S. Army
United States Army
The United States Army is the main branch of the United States Armed Forces responsible for land-based military operations. It is the largest and oldest established branch of the U.S. military, and is one of seven U.S. uniformed services...
and U.S. Marine Corps
United States Marine Corps
The United States Marine Corps is a branch of the United States Armed Forces responsible for providing power projection from the sea, using the mobility of the United States Navy to deliver combined-arms task forces rapidly. It is one of seven uniformed services of the United States...
, it is normally deployed in the mortar platoon
Platoon
A platoon is a military unit typically composed of two to four sections or squads and containing 16 to 50 soldiers. Platoons are organized into a company, which typically consists of three, four or five platoons. A platoon is typically the smallest military unit led by a commissioned officer—the...
of an infantry
Infantry
Infantrymen are soldiers who are specifically trained for the role of fighting on foot to engage the enemy face to face and have historically borne the brunt of the casualties of combat in wars. As the oldest branch of combat arms, they are the backbone of armies...
battalion
Battalion
A battalion is a military unit of around 300–1,200 soldiers usually consisting of between two and seven companies and typically commanded by either a Lieutenant Colonel or a Colonel...
.
Design
The M252 system weighs 91 lb (41 kg) completely assembled and is composed of the M253 Cannon (35 lb, 16 kg), M177 Mount (27 lb, 12 kg), M3A1 Baseplate (29 lb, 13 kg), and the M64A1 Sight Unit (2.5 lb, 1.1 kg). The mount consists of a bipodBipod
A bipod is a support device that is similar to a tripod or monopod, but with two legs. It provides significant stability along two axes of motion .-Firearms:...
and a base plate 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
Bipod
A bipod is a support device that is similar to a tripod or monopod, but with two legs. It provides significant stability along two axes of motion .-Firearms:...
mount. The M252 is a gravity-fired smooth bore
Smoothbore
A smoothbore weapon is one which has a barrel without rifling. Smoothbores range from handheld firearms to powerful tank guns and large artillery mortars.-History of firearms and rifling:...
system. Attached to the muzzle
Muzzle
A muzzle may be:* the snout of an animal* Muzzle , a device that covers an animal's snout* Muzzle , the mouth of a firearm* Muzzle , a song on The Smashing Pumpkins album Mellon Collie and the Infinite Sadness...
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
Firing pin
A firing pin or striker is part of the firing mechanism used in a firearm or explosive device e.g. an M14 landmine or bomb fuze. Firing pins may take many forms, though the types used in landmines, bombs, grenade fuzes or other single-use devices generally have a sharpened point...
.
History
The M252 is an adaptation of the British 81mm L16A2 mortarL16 81mm Mortar
The United Kingdom's L16 81 mm mortar is the standard mortar used by the British armed forces. It originated as a joint design by UK and Canada. The version produced and used by Australia is named the F2 81mm Mortar, whilst the version used by the U.S...
developed in the 1950s. It entered service with the U.S. Army and replaced the previous 81 mm M29 mortar
M29 Mortar
The M29 is a United States produced 81 millimeter calibre mortar. It began replacing the M1 Mortar in U.S. service in 1952 being lighter and with greater range. It was replaced by the M252 Mortar in 1984...
in 1986. It was adopted due to the extended range (from 4,500 meters
Metre
The metre , symbol m, is the base unit of length in the International System of Units . Originally intended to be one ten-millionth of the distance from the Earth's equator to the North Pole , its definition has been periodically refined to reflect growing knowledge of metrology...
to 5,650 meters) and enhanced lethality In the U.S. it is produced by Watervliet Arsenal
Watervliet Arsenal
The Watervliet Arsenal is an arsenal of the United States Army located in Watervliet, New York, on the west bank of the Hudson River. It is the oldest continuously active arsenal in the United States, and today produces much of the artillery for the army, as well as gun tubes for cannons, mortars,...
.
A much lighter version, the M252A1 was fielded for the first time in 2011. By reducing the number of parts and using lightweight materials, the total weight was reduced by 20.8 pounds. In the next several years, all U.S. Army M252s will be replaced by the M252A1. As part of the same program, a lighweight version of the M224 mortar
M224 Mortar
The M224 60 mm Lightweight Mortar is a smooth bore, muzzle-loading, high-angle-of-fire weapon used for close-in support of ground troops.-Description:The M224 system is composed of the*M225 Cannon *M170 Bipod...
was developed.
Crew
- The squad leader stands directly behind the mortar where he can command and control his squad. In addition to having general oversight of all squad activities, he also supervises the emplacement, laying, and firing of the weapon.
- The gunner stands to the left of the mortar where he can manipulate the sight, traversing handwheel, and elevating handwheel. He places firing data on the sight and lays the mortar for deflection and elevation. He makes large deflection shifts by shifting the bipod assembly and keeps the bubbles level during firing.
- The assistant gunner stands to the right of the mortar, facing the barrel and ready to load. In addition to loading, he swabs the bore after 10 rounds have been fired or after each fire mission. The assistant gunner is the person who actually fires the weapon.
- The first ammunition bearer stands to the right rear of the mortar. He has the duty of preparing the ammunition (charge settings, fuzeFuzeFuze Beverage, commercially referred to as just Fuze , is a manufacturer of teas and non-carbonated fruit drinks enriched with vitamins. Currently the brand consists of five vitamin-infused lines: Slenderize, Refresh, Tea, Defensify, and Vitalize...
s, etc...) and passing it to the assistant gunner. - The second ammunition bearer stands to the right rear of the mortar behind the ammunition bearer. He maintains and keeps a record of the ammunition in addition to the data corresponding to each fire mission. His 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 he provides local security for the mortar position.
Types of rounds
While the M252 does fire a weapon specific series of ammunition, it can also fire rounds from the M29 MortarM29 Mortar
The M29 is a United States produced 81 millimeter calibre mortar. It began replacing the M1 Mortar in U.S. service in 1952 being lighter and with greater range. It was replaced by the M252 Mortar in 1984...
(only at charge 3 or below though). The M252 Mortar can fire the following principal classifications of training and service ammunition
Ammunition
Ammunition is a generic term derived from the French language la munition which embraced all material used for war , but which in time came to refer specifically to gunpowder and artillery. The collective term for all types of ammunition is munitions...
.
- High explosive (HE)Explosive materialAn explosive material, also called an explosive, 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...
: Designations M821, M821A1, M889, M889A1, M372-series, and M362. Used against personnel and light materiel targets. - Smoke CartridgeSmoke bombA smoke bomb is a firework designed to produce smoke upon ignition. Smoke bombs are useful to military units, airsoft games, paintball games, self defense and pranks...
: Designations M819 and M375-series. Used as a screening, signaling, or marking munition. - Illumination (ILLUM): Designations M853A1 and M301-series. Used in night missions requiring illumination for assistance in observation.
- Training practice (TP): 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 M224 rounds have two fuzeFuze
Fuze Beverage, commercially referred to as just Fuze , is a manufacturer of teas and non-carbonated fruit drinks enriched with vitamins. Currently the brand consists of five vitamin-infused lines: Slenderize, Refresh, Tea, Defensify, and Vitalize...
types: the Multioption Fuze (M734
M734
The M734 Multi-Option Fuze shown in Figure 1 is a rangefinder and collision detection system used on 60mm, 81mm, and 120mm mortar shells as a trigger to detonate the shells at the most damaging heights of burst when combating four types of battlefield threats:* The rangefinder electronics is a...
) and the Point-Detonating Fuze (M935). The M734
M734
The M734 Multi-Option Fuze shown in Figure 1 is a rangefinder and collision detection system used on 60mm, 81mm, and 120mm mortar shells as a trigger to detonate the shells at the most damaging heights of burst when combating four types of battlefield threats:* The rangefinder electronics is a...
is used for the M720 HE round and can be set to function as proximity burst, near-surface burst, impact burst, or delay burst.
Method of propulsion
The range of mortars are controlled by what are referred to as "charges." Charges are semi-circular nitrocellulose donuts that resemble a puffy letter "C." Ammunition for the M252 mortar come with four charges. Longer range shots require more propellant than can be easily stored in the tail of the round, hence the necessity of the charges to be placed on the round. Once a target is ranged, the correct charge is placed on the round by removing the charges from the projectile. Once the charges are verified by the section leader, the round is dropped 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 tube. The primer detonates igniting the charge in the tail fin which in turn ignites any of the C-charges on the round. The expanding gas created by the burning charges push against the obturator band on the round, sealing the gasses and gives the round forward momentum. The round is accelerated by the gasses until it leaves the end of the tube.See also
- ArtilleryArtilleryOriginally applied to any group of infantry primarily armed with projectile weapons, artillery has over time become limited in meaning to refer only to those engines of war that operate by projection of munitions far beyond the range of effect of personal weapons...
- Military technology and equipment
- List of modern weapons
- List of artillery
- List of crew served weapons of the US Armed Forces