M18A1 Claymore Antipersonnel Mine

The M18A1 Claymore Antipersonnel Mine is a weapon (Anti-personnel mine) used by U.S.. It is named after the large Scottish sword, by the inventor, Norman A. MacLeod. The Claymore is designed to fire steel balls (700) (shrapnel) out to about 100 meters (328 ft) across a 60° arc in front of the device, which stands just off the ground. It is designed primarily to be used in ambushes and as an anti-infiltration device against enemy infantry, however it is also of some use against soft-skinned vehicles.

Nomenclature

The proper nomenclature for the Claymore Land mine in use with the United States military is Mine, AntiPersonnel, M18A1. Other countries employ the same, or similar mines, with different designations. Examples are the former Soviet Union models MON-50, MON-90, MON-100, MON-200; MRUD (Serbia); No. 6 (Israel); MAPED F1 (France); Mini MS-803 (South Africa), and more.

Operation and Effect

The Claymore mine is typically employed in one of three modes: Controlled, Uncontrolled, and Time-delayed.

Controlled Mode (also known as Command Detonation) - The mine is detonated by the operator as the forward edge of the enemy approaches a point within the killing zone (20 to 30 meters (65 to 100 ft)) where maximum casualties can be inflicted. Controlled detonation may be accomplished by use of either an electrical or nonelectrical firing system. When mines are employed in the controlled role, they are treated the same as individual weapons and are reported for inclusion in the unit fire plan. They are not reported as mines; however, the emplacing unit must ensure that the mines are either removed, detonated, or turned over to a relieving unit. The M57 Firing Device is included with the M18A1 Claymore Mine so that it can be used in the controlled mode. When Claymore Mines are daisy chained together, one M57 firing device can initiate several claymore mines.
Uncontrolled Mode (also known as Victim Initiated Detonation) - Uncontrolled firing is accomplished when the mine is installed in such a manner as to cause an unsuspecting enemy to detonate the mine. Mines employed in this manner must be reported and recorded as land mines. There are many mechanisms that can be used to initiate the M18A1 in uncontrolled mode, including the M142 Multipurpose Firing Device, M5 Pressure Release Device (mousetrap), tripwires, strikers, infrared sensors, acoustic & vibration sensors.
Time-delayed Mode - Time-delayed firing involves the fitting of a short timed fuse and a fuse igniter to the mine to allow the mine to be used as an anti-pursuit deterrent. This, anecdotally, may be combined with a CS grenade or bag containing the irritant contained in a CS grenade. The mine is emplaced quickly oriented on the direction pursuers are most likely to take and the fuse ignited before the position is abandoned.

When detonated, the M18A1 Claymore delivers spherical steel fragments over a 60° fan-shaped pattern that is two meters high (6 ft) and 50 meters (165 ft) wide at a range of 50 meters (165 ft). These fragments are moderately effective up to a range of 100 meters (328 ft) and can travel up to 250 meters (820 ft) forward of the weapon. The optimum effective range (the range at which the optimal balance is achieved between lethality and area coverage) is 50 meters (165 ft).

Landmine Bans

When in use by the US Military, the M18A1 Claymore Anti-Personnel Mine is most often command-detonated. Such use is permitted by the Mine Ban Treaty. However, use of Claymore mines in uncontrolled (tripwire) mode is prohibited by the treaty.

Because of the simplicity of the M18A1, it is readily used in uncontrolled mode, and as such, is frequently listed in efforts to ban anti-personnel mines.

While the United States has been an active participant in worldwide demining operations, it has not signed any landmine banning treaties. It is a requirement for the individual US soldier & Marine to know how to properly deploy and emplace the M18A1 landmine.

Theory: Misznay-Schardin effect

The M18 is based on the Misznay-Schardin effect, the behaviour of sheets of explosive that was independently discovered in WWII by Misznay, a Hungarian, and Schardin, a German. When the explosive detonates in contact with a metal object, the explosion is primarily directed away from the metal. Schardin spent some time developing the device as a side-attack anti-tank weapon, but development was incomplete at the end of the war.

M18

Following the massed Chinese attacks during the Korean War, the US Army developed the German design into an anti-personnel weapon that would fire hundreds of small ball-bearings in one shot. The rear of the device was a steel sheet covered with the explosive, and in front was an air space packed with the shot. When the explosive detonates the majority of the force is directed forward, sending the balls out the front at high velocity. Claymores were not buried like mines but were placed above ground pointed towards the likely location of the enemy.

M18A1

The M18A1 was standardized in 1960 for the Vietnam War, and replaced the M18 antipersonnel weapon. Both weapons are similar in appearance and functioning. The M18A1 has an olive coloured plastic casing (inert training versions are blue) with the words "Front Toward Enemy" on it. It is 21.5 cm (8 in) long, 8 cm (3 in) high, and 3.5 cm (1.5 in) deep with two sets of adjustable legs. Inside is 650 grams (1.5 lb) of plastic explosive and 700 steel ball-bearings. It is equipped with a knife edge style sight on currently fielded models (older models featured a fixed plastic slit-type sight which was not as effective for aiming and resulted in the mine being aimed too low, shortening the blast radius), and two detonator wells. The weapon and all its accessories are carried in the M7 bandoleer. An instruction sheet for the M18A1 is attached to the inside cover of the bandoleer.

References

External links

Explosive weapons | Area denial weapons | Cold War weapons of the United States | Modern American weapons | Landmines

M18 Claymore | Claymore | クレイモア地雷 | Claymore-miina

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