Claymore Mine - M18A1 Fragmentation Antipersonnel Mine
This information has been extracted from GTA 5-10-10, July 1965, Mine Card.  The Claymore (i.e. "Great Sword") directional mine was named after the large two edge sword used by Scottish Highlanders.  The 700 steel balls embedded in the explosive charge were supposed to blast out across the surface of the ground in a 60 degree wide swath of destruction.  The blasting cap was activated by the "clacker" firing device that generated a small electrical charge when squeezed quickly.  The rule of thumb was to squeeze the clacker several times to ensure the mine detonated when the enemy was in the kill zone of the weapon.

Soldiers in the 1st Battalion 6th Infantry carried these Claymore mines and  used them
near defensive positions and in mobile minefields known as "mechanical ambushes" or "MAs."  The
mines could be employed on a trail or likely avenue of enemy approach allowing a small unit effectively
to cover a larger area.  When Vietnamese civilians were known to be in the area of operations, MAs
could only be used during the curfew hours - generally 1800 to 0700 hours.  In areas with proper
military and civilian clearance, they could be used at any time.  Claymore mines used as mechanical
ambushes could be set up with either a taught tripwire (that fired upon release) or a slack tripwire
(that fired upon closure).  Several Claymores could be daisy chained together with explosive "det cord"
to provide greater coverage and destruction.  A small battery designed for the purpose or old PRC-25
or PRC-77 radio batteries hidden near the devices were used as the source of electrical power for

The location of all mechanical ambushes had to be reported to the Tactical Operations Center as
either a encoded map grid or as a direction and proximity from a known friendly unit location.  These
grid locations were recorded meticulously.  In order to avoid civilian or friendly casualties, the mines
were disarmed each morning.  This could be dangerous work if the Viet Cong had detected the mine
and put booby traps near the location.  When Claymores were used in defensive positions, one danger
was that daring Viet Cong soldiers would crawl close enough to turn the directional mines around.
It was just as nerve-racking to have to crawl out to the mines to ensure they were pointed toward the

In 1970, several defective lots of the directional mines were issued to soldiers in the Americal Division.
Rather than exploding as intended, the blasting cap merely knocked a chunk out of the corner of the mine.
Some soldiers unwisely gouged the explosive from the mine to use for heating their C-rations.  A small
chunk of the explosive would burn quickly to heat the can of food.  While some sought to blame the
malfunctions on mines that had been tampered with as a substitute for heat tablets, there was no question
that several defective lots of  the Claymore mines were issued to troops in combat.

For a detailed look at the development of the Claymore maine, use this link.

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