Monday, 4 June 2018

American Projectiles and Explosives - Tree Suspension Device and Anti-Tank Mines (Part 1)

American Projectiles and Explosives

Tree Suspension Device


General: The Tree Suspension Device M18 for smoke grenades is designed to provide a quick and simplified means for suspending standard burning-type smoke hand grenades from trees and foliage to permit emission of smoke above forests and foliage, where it is more readily visible to air observer.  It must be used with the Chemical Grenade Projection Adapter M2 assembled to any of the following hand grenades: AN-M8, M16, or M18.

Description: The device has a small cardboard tube into which is loosely packed about a ten-foot length of heavy rayon line.  Attached to each end of this line are two light metal cables, one for fastening to the body of the grenade and the other for fastening to the stabilizer of the Adapter M2.  It also has a heavier metal set-back ring to replace the set-back band issued with the chemical grenade projection adapter.  This heavier set-back ring retains the grenade safety lever in a safe position after removal of the fuze safety pin, releases the safety lever by set-back action upon being fired, and separates the grenade from the adapter by set-back action against the clips of the adapter, upon being fired.

Assembly: The device is assembled for use by slipping the double loop of cable over the grenade body under the safety lever.  The set-back ring is slipped over the bottom of the grenade so that it holds the safety lever in place, and the set-back band issued with the grenade is discarded.  The grenade is assembled to the adapter, and the single loop of cable is slipped over the adapter fins and secured to the stabilizer tube.  The rifle or carbine is prepared for firing in the usual manner, using positions 3 or 4, at an angle of elevation of 50 or 70 degrees and, normally with the butt of the gun supported by soft earts or other resilient material to avoid the possibility of cracking the stock.

Operation: Upon firing, the entire assembly is projected forward, and the set-back ring strikes the clips sharply, separating the grenade from the adapter.  Because of the construction of the adapter, it tends to slow down as soon as it is separated from the grenade.  In doing so, pulls the rayon line from the cardboard tube.  The grenade then flies through the air, with the adapter trailing at the end of the cord.  Upon reaching a tree, the cord and adapter become entangled on branches or foliage, suspending the smoking grenade.

Land Mines


Mine Types: There are two common types of land mines: anti-tank and anti-personnel.  Anti-tank mines, designed to immobilize track or wheeled vehicles, vary in the amount of explosive they contain, the normal charge being 6 to 12 pounds.  They are used in mine fields or road blocks.  Anti-personnel mines are used primarily to produce casualties to personnel, and, secondarily, to give local security and warning.  The explosive charge varies from 1/4 to 4 pounds.  Other, less common, mines are classified in the general categories of improvised, dummy, and practice.

Firing Devices: Firing devices are classified in accordance with the method of their initiation; that is, pressure, pull, tension-release, or pressure-release.  The initiating action causes the device to function by chemical reaction, friction, percussion, or the closing of an electrical circuit.

Anti-tank mines generally have a main fuze which is employed as the primary initiating device; however, some anti-tank mines have supplementary activator wells on the side and bottom for booby trapping.

Marking: Mines can be identified by their color and markings.  Land mines are generally painted lusterless olive drab with a yellow base and black markings, while practice mines are painted blue with white markings and dummy mines are black.

Army and Navy Types: The Navy does not design land mines, but it has produced three firing devices for use with demolition charges - the Firing Devices Mk 1, Mk 3, and Mk 15.  The Navy also produced the practice firecracker.

Anti-Tank Mines

M1A1 (Obsolete)

Diameter: 8 inches
Height (with spider): 4 inches
Height of body: 2.75 inches
Total weight: 10.6 pounds
Cast TNT weight: 6 pounds
Material: Steel
Fuzing: M1A1, M1A2

Components: The metallic Anti-Tank Mine M1A1 has three main components: loaded body, fuze, and spider.  The spider fits over the fuze to increase the effective size of its head.  The steel body is a squat cylindrical container of light steel filled with high explosive.  A carrying ring is attached to its side.  The flanged rim around the top is notched for attaching the spider.  In the center of the top is the cavity for the fuze and booster; the booster fits into the cavity and locks into place.  The spider is a ring with two cross members pressed from a single sheet of metal.  Hooks on the spider engage the flange on the mine body, and the center hub of the spider rests on the striker head of the fuze.  When the mine is packed, the spider is placed over the bottom of the steel body to save space.

Arming: The safety fork is not removed until after the mine is laid; and, after removal, the fork is left beside the mine, attached to its cord, never between the body and the spider.  Before the mine is taken up, the safety fork is replaced.

Color: The bottom and 3/4-inch of the side are painted yellow; the rest of the mine is painted olive drab.

Remarks: The M1, the original model, is no longer being manufactured or issued.  The principal difference is that, in the Mine M1, the booster is an integral part of the fuze; in the Mine M1A1 the booster is a separate part and issued assembled in the fuze cup of the mine.

Protective bag covers made of moisture-resistant, mildew-proof fabric are provided with this mine to prevent foreign matter from working between the mine body and the spider.  The cover is cylindrical in shape, 8.75 inches in diameter, 9 inches high, and open at one end.  The Mine M1A1 is being replaced by the M6.

M4 (Obsolete)

Diameter: 8 inches
Height (with spider): 4 inches
Total weight: 10.6 pounds
Cast TNT weight: 6 pounds
Material: Steel

Components: The metallic Anti-Tank Mine M4 is identical to the M1A1 type except for the booster, the fuze, and the activator wells.  The M4 has one activator well on the bottom and one on the side.  Since the booster, after loading, becomes an integral part of the mine, and since the M1A1 and M4 boosters and fuzes are not interchangeable, it is especially important that the Mines M1A1 and M4 and their respective fuzes be kept separate.  However, the two mines are assembled, armed, and employed in the same manner.  The advantage of the Mine M4 is that the internal construction of the M4 fuze makes it safe to re-use, because it is not made more sensitive by repeated light blows.

Booster: The M4 booster is identical with M1A1 booster, except that it has a flat top with a crossed scar to insure rupture of the booster shell by the detonator, while the M1A1 booster has a cavity int he top to receive the protruding primer and detonator of the M1A1 fuze.

Arming: The safety fork is removed from the fuze by pressure of the thumbs on the prongs.

Color: The bottom and 3/4-inch on the side are painted yellow; the rest of the mine is painted olive drab.

Remarks: The Mine M4 is being replaced by the M6.

The M4 also has a protective cover bag.


Diameter: 10 inches
Height: 5.5 inches
Total weight: 14.5 pounds
Weight of filler: 5.6 pounds
Type of filler: TNT or Tetrytol
Material: Pottery and impregnated felt

Components: The cylindrical mine body consists of a ceramic bowl containing the high explosive, with a ceramic plate which acts as the spider.  These components are separated by a cushion of rubber or similar material and enclosed in asphalt-impregnated felt and tarred paper.  There is a threaded opening in the top of the mine for assembly of the fuze and a bakelite plug in the bottom, which may be removed for the attachment of an anti-removal device.

Color: The mine is painted olive drab and marked in yellow

Remarks: This is a non-metallic mine in order that it may not be detected by an electro-magnetic mine detector.

An anti-lifting device may be attached by removing the rubber plug in the bottom of the mine; however, use of a metal device tends to defeat the purpose of designing the mine and fuze with no metal parts.

This mine is considered a substitute standard item by the Army Ordnance Department.

Next Time: Anti-Tank Mines (Part 2)

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