LINEAR ANTI-PERSONNEL Mines FRAGMACORD
And
MK 57 Demo Sheets
XM-37 Linear Anti-personnel mine (FRAGMACORD): This was the first linear AP mine to be tested was the XM 37. A limited test was performed in 1967, but due to a number of factors it did not receive a thorough evaluation. Fragmacord, as it was called was a linear anti-personnel mine consisting of 25 foot lengths of flexible explosive cord (100 gr/ft detonating cord where standard detonating cord is 55gr/ft). It was 1/2inch in diameter with 1 inch rings spaced 1/4" inch apart along the length of cord to provide flexibility in handling and emplacement. It could be initiated by electric or non-electric caps. In laboratory tests the lethal area was determined to be 100feet in all directions, but the danger zone could extend well beyond this.
The XM-37 was later improved and became the XM-61 Linear fragmentation anti-personnel mine. This non directional mine consisted of a 25 length of waterproof, 7/16 diameter detonating cord (100 grains/ft) with approximately 150 coiled fragmentation ring units assembled to it. The entire mine was olive drab in color and bared no markings. Attached picture illustrates the XM61 linear frag AP mine and its employment. The fragmentation rings were improved and made of square wire and serrated on the inside to provide better fragmentation upon detonation. The 1.25 long fragmentation rings were spaced evenly along the length of the detonating cord at 2 intervals. The XM 61 AP mine like the XM-37 could be shortened as required by cutting between the fragmentation rings, or if a longer mine was required, individual mines could be connected together with a metal coupling assembly.
Detonation of the mine was accomplished with a standard electric or non electric blasting cap which is either control fired or assembled to a standard firing device. Upon detonation of the mine, the serrated rings produced fragmentation covering a circular area along the entire length of the mine.
The following were some suggested employment tactics:
(a) Placed in a ditch where the enemy is expected to take cover, prior to an attack, and detonated remotely.
(b) Attaching several cords together and emplaced around the entire perimeter either on the ground or in the trees. Primed to detonate all at once or in sections.
(c) Booby trap trails by cutting into smaller sections and wrap around tree trunks waist high. Rig with a trip wire.
(d) Use as an improvised hand grenade. Coil or ball the stripe and attach blasting cap with short piece of safety fuse.
These types of linear AP mines, had a very short life, field tests did not match the predicted controlled tests. By mid 1968 the mines were no longer being produced, but mines still in the inventory in VN were used by whomever or when seen fit. Several hundreds of feet of these mines were issued not only to the SpecOps community, but also to various Infantry Divisions and companies of the75[SUP]th[/SUP] (Ranger) Infantry. The M-18 Claymore continued to be the best AP mine for fragmentation.
CHARGE KIT, EXPLOSIVE SHEET, MK 57 MOD 0
In late 1969, the Navy SpecOps community Swimmer Weapons System introduced the MK-57 sheet explosive kit for use as an AP mine. This charge consisted on serrated steel squares placed on data sheet (flexible sheet explosives) that was then glued to Styrofoam. The Styrofoam allowed for the charge to be somewhat buoyant. This sheet explosive could be cut into what ever shape or size wanted; normally it would be wrapped around a tree and set up for an ambush. Fragmentation patterns were OK, but still not as good as the Claymore. While the SEALs liked the charge (and it is still in their inventory), the SF community in VN didnt care for it so much. The charge was used numerous times in VN and 2 after action reports mention its use in Laos.
The Mk 57 Mod 0 Explosive Sheet Charge Kit is intended for both surface and underwater use. This self-contained antipersonnel weapon kit may be used in both offensive and defensive applications.
The Mk 57 Charge Kit consists of four 10-inch by 36-inch antipersonnel weapon sheets (Mk 56 Mod 0 Explosive Sheet Charge) and the following components: four M57 Firing Devices, one M40 Test Set, sixteen M4 Blasting Caps, four rolls of c1othbacked ordnance tape, and four M7 bandoleers. The components of the Mk 57 Charge Kit are described as follows:
Mk 56 Mod 0 Explosive Sheet Charge. The Mk 56 Charge is a light weight fragmentation charge supplied as flexible sheets. The shrapnel fragments are cut from cold rolled steel. Each fragment measures 1I16-inch by l/4-inch by 114-inch and each sheet charge contain approximately 5,000 fragments. The shrapnel fragments are retained by a layer of nylon mosquito netting. A rubber adhesive is used to bond the netting, fragments, sheet explosive, and foam together. The adhesive also acts as a sealer for the foam.
The M57 Firing Device is a hand-held electric pulse generator used to initiate the blasting caps which detonate the explosive sheet charge. Same firing device that was used with the M-18 Claymore mine.
M40 Test Set. The M40 Test Set is a device for checking the continuity of the initiating circuit of the firing device. Again same as used with the Claymore
