Monday 7 May 2018

American Projectiles and Explosives - Hand Grenades (Part 1)





American Projectiles and Explosives




Grenades




General

The design of hand grenades has been confined by several limiting technicalities, as follows: the grenade must be small and light; its range is short; there is no set-back or creep force of significance in the throwing operation; and the grenade must be rugged and safe enough to be carries on the bodies of troops.

Hence, despite the many tactical purposes, anti-tank, anti-personnel, screening, etc, hand grenades are generally of the same shape, size, and fuze action.





Fragmentation Mk II, Mk IIA1; also Fuze M204


Overall length: 4.5 inches
Diameter: 2.25 inches
Color: Olive drab
Weight: 1.4 pounds
Filling: Flaked and granular TNT
Weight of filling: 1.75 ounces

Fuze: M204
Delay: 4 to 5 seconds


Description: The Fragmentation Grenade Mk II has a serrated cast-iron body of the familiar "pineapple" design.  The grooves run both horizontally and vertically to assist in the formation of uniform fragments of effective size.

This grenade is issued loaded and fuze with Igniting Fuze M204.  This Fuze M204 produces no noise other than that of the impact of the striker on the primer, and emits no smoke or sparks during its burning.  The fuze consists of a body, striker, safety lever, and safety pin.  The body of the fuze is cylindrical in shape and is threaded for assembly to the grenade.  It contains the primer, a delay element sufficient to give an average delay of 4.5 seconds, and a detonator of PETN.  At the top of the body, one side is extended and slotted to form a point of fulcrum for the attachment of the safety lever.  The striker is retained by the safety lever.  The lever is hooked under the lip of the fuze body, extends across the head of the fuze and over the striker, and curves downward in an arc that conform to the shape of the grenade body.  The lever is held in position for shipping and handling by a split safety pin which passes through the safety lever, through the fuze body, and over the striker to protrude on the other side, where the pin is spread so that a pull of between 20 and 30 pounds is required to withdraw it.


Operation: When the safety pin is withdrawn preparatory to throwing, the lever is held in place by the hand holding the grenade.  When the grenade is thrown, the lever is released.  The striker, driven by its spring, throws off the lever and rotates about its pivot to impinge on the primer.  The primer ignites the delay element, which takes from 4 to 5 seconds to burn through to a relay element which flashes through a flash channel to ignite the detonator.  Explosion of the PETN detonator, detonates the main charge of the grenade.

The grenade can be thrown about 35 yards.  Effective fragmentation covers an area of 30-yard radius, but fragments may travel as far as 200 yards.


Earlier models: This grenade replaces an earlier model, the Mk IIA1, which was identical to the Mk II except for the fuze and the filling, the Mk  IIA1 being issued with the Fuze M10A3.  The only external difference is that the safety lever fits over rather than under the lip of the fuze body.  The Fragmentation Grenade Mk II is filled with 3/4 ounce of E.C. powder.







Offensive Mk IIIA1 and Mk IIIA2; also Fuzes M6 and M206A1


Overall length: 5.35 inches
Diameter: 2.125 inches
Color: Black
Weight: 0.84 pounds

Fuze: M206A1
Delay: 4.5 seconds


Description: The Offensive Grenade Mk IIIA2 consists of a cylindrical pressed-fiber body and a charge of pressed TNT.  The head contains a threaded fuze hole which is sealed by a water-proof paper disc.

It is fuzed with Detonating Fuze M206A1, which has a delay varying between 4.3 and 4.8 seconds.  The fuze consists of a threaded metal body which contains the primer, delay element, and detonator, and to which a spring-drive striker is attached.  The striker is restrained by the safety lever, which hooks over the lip of the body and passes across the head of the body, over the striker, and down the side of the grenade.  The lever is held in place during shipping and handling by a split safety pin which passes through the safety lever, through the fuze body, and over the striker, to protrude on the other side, where it is spread so that a pull of between 10 and 30 pounds is required to withdraw it.  This fuze is distinguished from igniting fuzes by the red sealing compound, instead of green, used to seal the detonator into the fuze.


Operation: When the safety pin is removed preparatory to throwing, the lever is held in place by the hand holding the grenade.  When the grenade is thrown, the lever is released.  The striker, driven by its spring, throws off the lever and rotates about its pivot to impinge on the primer.  The primer ignites the delay element, which takes about 4.5 seconds to burn through to the detonator.

The explosion of the detonator sets off the main charge, producing a blast effect.  This blast is not effective against personnel except at very short ranges or in enclosed spaces.


Earlier models: The Offensive Grenade Mk IIIA1 differs from the Mk IIIA2 in that the ends of the grenade body are of sheet metal and the grenade weighs 0.875 pounds fuzed.  The Mk III had metal ends and contained only 0.27 pounds of TNT.  It was shipped with a wooden plug in the fuze well.  The M6A1, M6A2, and M6A3 models of this fuze may be encountered.  These modifications have been declared unsafe for use and should be destroyed.


Remarks: The Hand Grenade Mk IIIA2 has been taken out of production, but large quantities of them still exist.






Smoke (W.P.) M15; also Fuzes M6A3, M10A3, and M200A1



No picture available

Overall length: 5 inches
Diameter: 2.5 inches
Color: Blue grey
Filling: White Phosphorus

Fuze: M6A3
Delay: 4.5 seconds


Description: This grenade is of the bursting type and contains white phosphorus in a sealed cylindrical container.  The body corners are rounded.  It is fuzed with the Detonating Fuze M6A3, which has a delay varying between 4.3 seconds and 4.8 seconds.  The fuze consists of a threaded metal body which contains the primer, delay element, and detonator, and to which a spring-driven striker is attached.  The striker is restrained by the safety lever, which hooks over the lip of the body and passes across the head of the body, over the striker, and down the side of the grenade.  The lever is held in place during shipping and handling by a split safety pin which passes through the safety lever, through the fuze body, and over the striker, to protrude on the other side, where it is spread so that a pull of between 10 and 30 pounds is required to withdraw it.  This fuze is distinguished from igniting fuzes by the red sealing compound, instead of green, used to aid in sealing the detonator into the fuze.  It differs from the Detonating Fuze M10A3 in that the safety lever is straight, while that of the M10A3 is curved.  It differs from the Detonating Fuze M200A1 int hat the length of the body is approximately four inches, as compared with a body length of two inches for the M200A1.  The detonator consists of a seven-grain primer charge and a 13.5-grain tetryl charge.


Operation: When the safety pin is removed preparatory to throwing, the lever is held in place by the hand holding the grenade.  When the grenade is thrown, the lever is released.  The striker, driven by its spring, throws off the lever and rotates about its pivot to impinge on the primer.  The primer ignites the delay element, which takes about 4.5 seconds to burn through to the detonator.

When ignited by the delay element, the detonator bursts the case and scatters the phosphorus over an area about 25 yards in diameter.  The phosphorus ignites spontaneously, and the scattered pieces will burn for about 30 seconds.






Gas CN-DM-M6, CN-M7, and CN-M7A1; also Fuze M201A1


Overall length: 5 inches
Diameter: 2.5 inches
Color: Blue grey

Filling:
-M6: Cloracetophenome, Diphenylamine, Chloraisine, burning mixture
-M7: Cloracetophenome, burning mixture

Fuze: M201A1
Delay: 2 seconds


Description: These grenades are of the burning type; they do not explode.  They have a cylindrical body made of tin plate.  The M7A1 has a half-inch gas port in the bottom and four ports in the head, covered by small squares of adhesive tape.  A center hole is placed through the CN mixture.  At the top of the hole is the starter mixture.  The M6 and M7 have three lines of six gas ports in the body and four ports in the head, covered by small squares of adhesive tape.

The Fuze M201A1 threads into the top of these grenades.  It is essentially the same as the Igniting Fuze M10A3 used in the fragmentation hand grenade.  However, there is only a two-second delay element, an igniter, and no detonator.  This results in a fuze with a much shorter body.  At the top of the body, one side is extended to form a lip for the attachment of the safety lever; the other side forms a hinge to carry the spring-loaded striker.  The striker is restrained by the safety lever.  The lever is hooked over the lip of the fuze body and extends across the head of the fuze, over the striker, and down the side of the grenade.  The lever is held in position for shipping and handling by a split safety pin which passes through the safety lever, through the body, and over the striker, to protrude on the other side, where it is spread so that a pull of between 20 and 30 pounds is required to withdraw it.


Operation: When the safety pin is removed preparatory to throwing, the lever is held in place by the hand holding the grenade.  When the grenade is thrown, the lever is released.  The striker, driven by its spring, throws off the lever and rotates about its pivot to impinge on the primer.  The primer ignites the delay element, which takes about 2 seconds to burn through to the igniter.  The igniter ignites the starter mixture, which creates enough heat to vaporize the chemical ingredients.  The pieces of adhesive tape covering the gas ports are blown or burned off and gas is emitted  The gas generation reaches full volume three seconds after the safety lever is released, and gas is emitted for from 20 to 60 seconds.  The M7A1 has an average burning time of 45 seconds.


Remarks: The M7A1 is an improved model of the M7, which is now substitute standard.  The tendency of the M7 to flame or explode upon ignition has been eliminated in the M7A1, which also produces more than double the concentration of CN smoke and vapor.





Smoke, White, H.C., AN-M8, and Colored, M18 and M16; also Fuze M201


No picture available

Length: 5 inches
Diameter: 2.5 inches
Color: Blue grey

Filling:
-AN-M8: Hexachlorethane-zinc
-M18: Colored smoke mixture

Fuze: M201
Delay: 2 seconds


Description: These grenades have four ports in the head.  These are covered by small squares of adhesive tape.  The Grenades M18 produce seven colors of smoke: red, orange, blue, green, black, violet, and yellow.  The M16 is a limited standard colored-smoke grenade and differs from the M18 in that it produces smoke for 2.5 minutes, while the M18 produces smoke for one minute, and the AN-M8 produces a white smoke for three minutes.

The Fuze M201 threads into the top of these grenades.  It is essentially the same as the M10A3 used in the fragmentation hand grenades.  However, there is only a two-second delay element, an igniter, and no detonator.  This results in a fuze with a much shorter body.  At the top of the body, one side is extended to form a lip for the attachment of the safety lever; the other side forms a hinge to carry the spring-loaded striker.  The striker is restrained by the safety lever.  The lever is hooked over the lip of the fuze body and extends across the head of the fuze, over the striker, and down the side of the grenade.  The lever is held in position for shipping and handling by a split safety pin which passes through the safety lever, through the fuze body, and over the striker, to protrude on the other side, where it is spread so that a pull of between 20 and 30 pounds is required to withdraw it.


Operation: The igniter ignites the starter mixture, which initiates the smoke mixture.  The pieces of adhesive tape covering the gas ports are blown or burned off and gas is emitted for approximately 3.5 minutes.

The volume of smoke generated by a grenade is generally too small for screening purposes.  Although these grenades may be used to patch gaps in a larger screen, the authorization is for signals.


Remarks: The presence of moisture will cause these grenades to ignite spontaneously.  If a fire should occur in such munitions, an attempt should be made to remove and segregate the burning items.  Neither water nor the usual chemical extinguishers should be used in an attempt to extinguish such fires.

The Smoke Grenade M16 is designated as a substitute standard item.







Smoke, Red, AN-M3, also Modified Fuze M201


Length: 5.5 inches
Diameter: 3 inches
Color: Blue grey
Filling: Red smoke mixture

Fuze: Modified M201
Delay: 2 seconds


Description: This grenade differs from the other smoke grenades in that the body is assembled in a cylindrical outer container.  This container has eight smoke-emission ports in its top.  It also has three light metal flaps welded to the side, which may be bent outward at right angles to furnish bearing for supporting the grenade in snow, mud, or other soft surface.  With the outer container, this grenade is slightly larger than the ordinary smoke grenade.

The Fuze M201 has been modified by shortening the safety lever so that it does not protrude down the side of the grenade.  At the top of the body, one side is extended to form a lip for the attachment of the safety lever; the other side forms a hinge to carry the spring-loaded striker.


Remarks: This grenade is used for signaling, especially in snow.




Next Time: Hand Grenades (Part 2)

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