Monday, 27 June 2016

Italian Explosive Ordnance - Bombs (Part 2)

Italian Explosive Ordnance


40kg GP H.E. Bomb


Overall length: 32.3 inches
Body length: 19.7 inches
Body diameter: 9 inches
Tail length: 16.1 inches
Tail width: 9 inches

Type of filling: TNT
Weight of filling: unknown
Total weight: 40 kilograms

Fuzing: Tail only - Type N-3
Color and markings: Overall grey; red nose

Description:  The bomb has a steel body and nose in one piece.  The tail is of sheet-metal construction with a strengthening band at the end.  The tail unit is bolted to four square lugs on the body.
Remarks: This bomb is very similar to 40kg gas bomb, except for filling.

50kg GP H.E. Bomb

Overall length: 40.5 inches
Body length: 21.7 inches
Body diameter: 9.9 inches
Wall thickness: 0.25 inch
Tail length: 18.4 inches
Tail width: 9.9 inches

Type of filling: Amatol
Weight of filling: 29.2 kilograms
Total weight: 59.31 kilograms

Fuzing: Tail only - Type C or Y
Color and markings: Overall dull blue.
Description: The bomb body consists of a base section and a nose section, both steel.  Screwed into the nose is a pointed steel block, pierced to take a suspension link.  The tail is secured to the base plate, which is attached to the casing with one row of screws.  The tail assembly consists of four vanes, tail cone, and corrugated strengthening ring, all sheet metal.  The bomb can also be suspended horizontally.

100kg GP H.E. Bomb

Overall length: 51.3 inches
Body length: 32.5 inches
Body diameter: 10.7 inches
Tail length: 22 inches
Tail width: 10.7 inches

Type of filling: TNT
Weight of filling: 50.6 kilograms
Total weight: 100 kilograms (approx.)

Type of filling: Amatol
Weight of filling: 49.5 kilograms
Total weight: 100 kilograms (approx.)

Fuzing: Tail only - Type C-1 or Y-1
Color and markings:
-TNT filled: Overall grey; red nose
-Amatol filled: Overall dull blue; red nose
Description:  The bomb body is a drawn-steel tube to which is riveted a cast-steel nose pierced to take a suspension link.  The base plate is attached to casing with two rows of screws.  The tail assembly is sheet metal consisting of four vanes, cone, and corrugated reinforcing ring, all attached to the bomb base.  The bomb can be suspended vertically or horizontally.

250kg GP H.E. Bomb

Overall length: 73.8 inches
Body length: 35.4 inches
Body diameter: 17.6 inches
Tail length: 39.4 inches
Tail width: 17.6 inches

Type of filling: TNT
Weight of filling: 125.7 kilograms
Total weight: 259.1 kilograms

-Nose: Type A
-Tail: Type O
Color and markings: Overall grey; red nose

Description: The bomb casing is a drawn-steel tube with a cast-steel nose riveted to it.  The base plate has a double flange and is attached to the casing with a double row of screws.  A cast-alloy tail is attached to the upper flange of the base plate with screws.  A lug is secured to the body near the center of gravity for horizontal suspension.

500kg and 800kg GP H.E. Bombs


Overall length: 96.6 inches
Body length: 52 inches
Body diameter: 18 inches
Tail length: 35.7 inches
Tail width: 18 inches
Type of filling: TNT
Weight of filling: 216 kilograms
Total weight: 508 kilograms


Overall length: 127.8 inches
Body length: 77.1 inches
Body diameter: 18 inches
Tail length: 52.8 inches
Tail width: 18 inches
Type of filling: TNT
Weight of filling: 357 kilograms
Total weight: 821.6 kilograms
-Nose: Type A
-Tail: Type O
Color and markings: Overall grey; red nose

Description: The bombs have a steel body and nose cast in one piece, with double-flanged base plate attached by double rows of screws.  The cast alloy tail is attached to the upper flange.  The 500kg and 800kg vary only in length and weight.
Remarks: A 630kg time bomb has been made from the 800kg by reducing the thickness of walls so as to use a greater explosive charge.

1000kg G.P. Bomb

Overall length: 140 inches
Body length: 94.5 inches
Body diameter: 20.5 inches
Wall thickness: 0.29 inch
Tail length: 45.5 inches
Tail width: 28 inches

Type of filling: TNT
Weight of filling: Unknown
Total weight: 1000 kilograms (approx.)

Fuzing: Nose fuze only - Unknown

Color and markings: Overall grey; Nose: red

Description: The bomb casing is made up of four pieces welded together: (1) the nose; (2) a cylindrical part; (3) a truncated cone; and (4) the conical part to which the tail fins are attached.  At about 30 inches from the rear, a steel diaphragm is welded inside the casing to contain the main filling before this point.

A steel nose plug carries a steel fuze adapter, and both these have serrated flanges to form seals against rubber packings which are counter-sunk into the relative surfaces on the bomb nose plug, respectively. A steel booster tube, about 1 and 1/4 inches in diameter, runs the length of the bomb; it is inserted from the tail end, where it is screwed into the tail cone, and at the nose end it is located by a sleeve which forms an extension to the fuze adapter.

A plug which is drilled to take the detonator, is screwed into the forward end of the booster tube; there is a felt washer beneath this plug.  An internal plug, which is located by grub screws, seals the booster charge at the rear.  A steel plug closes the booster tube at the tail end.  The booster tube contains penthrite.  Around the booster tube and forming a core to the main filling is a tube, 3 inches in external diameter, with a bore 2 inches in diameter; this is composed of annular rings of compressed TNT about 2 and 1/4 inches long.

Remarks: A glider attachment was used with this bomb.  The controls for the glider contain a gyro unit for azimuth and an airspeed unit to control the dive angle.

500kg GP H.E. Time Bomb

Overall length: 93.7 inches
Body length: 50.9 inches
Body diameter: 18.1 inches
Wall thickness: 0.25 inch
Tail length: 43.3 inches
Tail width: 18.1 inches

Type of filling: TNT
Weight of filling: 247 kilograms

Fuzing: Tail - Type N
Color and markings: Overall grey; red nose

Description: Main body and nose are cast in one piece.  In the nose is a centrally-located clockwork fuze and provision for four additional impact fuzes.  If a time fuze is used, impact fuzes can be made inoperative.  The cast aluminum-alloy tail is attached to the bomb by screws.

Remarks: A similar bomb weighing between 800 and 1000 kilograms is thought to have been used by the Italians.

Next Time: Italian Semi-Armor Piercing and Incendiary Bombs

Monday, 20 June 2016

Italian Explosive Ordnance - Bombs (Part 1)

Italian Explosive Ordnance


Italian bombs closely resemble Japanese bombs in that they are usually more than one-piece in construction, assembled by screws or rivets, or welded.  The Italian bomb is normally filled through the base, which is closed by a base plate attached by screws or rivets.  Normally, the tail unit fits over the base plate and is attached to the body or the base plate by screws or rivets, or, in case of the smaller bombs, by welding.  The tail units vary considerably in their design, but the tail diameter is usually the same as that of the body of the bomb to which it is attached.

Generally the bombs are of sheet steel, but some are constructed of cast aluminum alloy.  In most cases, the filling is cast TNT, but a large number have been found with an alternate filling of Amatol and TNT with aluminum powder.  A felt pad in the nose breaks the shock of impact on the explosive filler.  The bombs contain a booster, and an initiating charge in the fuze.

Normally the demolition bombs have a mild steel casing, while the armor-piercing bombs use hardened steel.  The wall thickness for the 24kg or large bombs ranges from 1/4 inch to 1/2 inch for light-cased and from 1/2 inch to 1 and 1/2 inch for heavy-cased.  This thickness varies for each bomb, increasing towards the nose.

Demolition bombs and chemical bombs, 100kg or less, usually have provision for tail fuzing only.  The tail fuzes are screwed into the base of the bomb.  These tail fuzes usually have very long arming spindles which extend the full length of the tail.  The end of the bomb tail is shaped to accommodate the arming vanes of the fuzes.  In the case of 20kg incendiary bombs, the tail unit is cut to allow the vanes to be situated half-way along the tail in order to insure limited terminal velocity for the vanes.  Nose and tail fuzing is normally used in demolition bombs of 160kg or above.

Antipersonnel bombs differ from the demolition bombs in the construction of the outer casing.  In one type, the filling is enclosed in a sheet container, on the outside of which a steel strip is wound spirally.  In another type, the filling is contained in a sheet-steel case which is enclosed by a larger container.  The space between the two containers is filled with steel fragments embedded in concrete.  These antipersonnel bombs are known as Type F and Type Mtr, respectively.

Italian bombs are either painted or galvanized as a precaution against corrosion.  The colorings are usually found on the nose and the body.  Distinguishing colors are identified as follows:

Type of Bomb ---- Body ---- Nose
Fragmentation ---- Blue ---- Red
High Explosive ---- Grey ---- Red
Antipersonnel ---- Black or Blue ---- Red
Incendiary ---- Reddish Brown ---- Red
Gas ---- Bright Yellow ---- Red
Practice ---- Grey ---- Grey

2kg Antipersonnel Bombs Types F and Mtr


Type F

Overall length: 6 inches
Body length: 4.5 inches
Maximum diameter: 2.75 inches
Type of filling: TNT
Weight of filling: 0.38 kilograms
Total weight: 1.72 kilograms
Type Mtr

Overall length: 6 inches
Body length: 4.5 inches
Maximum diameter: 2.75 inches
Type of filling: TNT
Weight of filling: 0.22 kilograms
Total weight: 1.87 kilograms

Fuzing: Tail - Type K
Color and markings: Overall black

-Type F: The bomb consists of a thin steel cylinder surrounded by a tightly coiled spring of rectangular cross section.  In certain assemblies of this type, the spring is enclosed by a thin case.  The object of the spring is to provide shrapnel effect.  In fragmentation, the bomb usually breaks into pieces about 1 inch by 0.2 inch by 0.18 inch.  The bomb has no tail unit.

-Type Mtr: The bomb consists of two cylinders of sheet metal.  The inner cylinder contains the explosives, and the outer cylinder is threaded at the top to take a screwed circular cover.  Between the two cylinders are small steel pellets embedded in concrete.
1. The bomb may be dropped singly or in containers.
2. These bombs are very similar to 1kg incendiary bomb and 1kg gas bomb
3. The bomb can also be used as a land mine by use of a pressure igniter.  

3kg Antipersonnel Bomb Type Mtr

Overall length: 12.1 inches
Body length: 8.2 inches
Body diameter: 2.7 inches
Tail length: 4.5 inches
Tail width: 2.7 inches

Type of filling: TNT
Weight of filling: 0.17 kilograms
Total weight: 3 kilograms

Fuzing: Nose - Type M
Color and markings: Overall blue or black.  Nose is painted red.
Description: The bomb body is thin sheet steel with a fuze adapter pressed and spot-welded into the nose.  A steel central tube, 7.1 inches long and 0.078 inches thick, contains the bursting charge of block TNT, recessed to take the base of the fuze and the detonator.  The space between the exploder container and the bomb's outside wall is filled with steel fragments embedded in concrete.  The tail is made of thin sheet metal, with four vanes strengthened by a band 0.39 inches in width.

4kg Antipersonnel Bomb Manzolini (Thermos)

Overall length: 12.3 inches
Body length: 7.3 inches
Body diameter: 2.75 inches
Wall thickness: 0.125 inch

Type of filling: TNT
Weight of filling: 0.67 kilograms
Total weight: 3.68 kilograms

Fuzing: Manzolini Type I and II
Color and markings: Overall buff or green
Description:  This bomb, with a steel body and aluminum top, resembles a thermos bottle.  The fuzes are very sensitive.  The fragments are lethal to 100 feet, with a maximum range of 300 yards.
1. Bombs fitted with self-destroying mechanism have an aluminum alloy fuze housing (visible where the fuze screws into the bomb).
2. Bomb does not explode on impact, but is designed to explode if moved, and is extremely sensitive to vibration.

12kg Antipersonnel Bombs Type F and Mtr.

Type F

Overall length: 32.4 inches
Body length: 17.3 inches
Body diameter: 3.5 inches
Wall thickness: 0.2 inch
Tail length: 14.5 inches
Tail width: 3.5 inches
Type of filling: TNT
Weight of filling: 1.93 kilograms
Total weight: 12.2 kilograms
Type Mtr

Overall length: 32.3 inches
Body length: 16 inches
Body diameter: 3.5 inches
Wall thickness: 0.2 inch
Tail length: 16.5 inches
Tail width: 3.5 inches
Type of filling: TNT
Weight of filling: 1.9 kilograms
Total weight: 12.88 kilograms

-Type F: Nose - Type F
-Type Mtr: Nose - Type J
Color and markings:
-Type F: Overall sky blue; Nose: red
-Type Mtr: Overall blue or black; Nose: red

-Type F: This bomb consists of a steel container around which are wound 25 turns of square steel wire, 0.2 inches thick.  The purpose of the wire is to provide shrapnel effect in fragmentation.  The tail assembly consists of four stamped sheet-metal vanes which are spot-welded to the base of the bomb.

-Type Mtr: This bomb is very similar to the Type F in appearance, but differs in construction of the body.  The body is a double-walled steel cylinder containing steel shrapnel embedded in concrete.  In manufacturing the bomb, the concrete-shrapnel filling was poured into the base of the bomb and then the tail unit was screwed into the outer wall of the bomb.

14kg Fragmentation Bombs Types I and II

Type I

Overall length: 22.1 inches
Body length: 13.5 inches
Body diameter: 4.2 inches
Wall thickness: 0.2 inch
Tail length: 6.4 inches
Tail width: 4.2 inches
Type of filling: TNT
Weight of filling: 2 kilograms
Total weight: 14 kilograms
Type II

Overall length: 22.1 inches
Body length: 13.5 inches
Body diameter: 4.2 inches
Wall thickness: 0.7 inch
Tail length: 6.4 inches
Tail width: 4.2 inches
Type of filling: TNT
Weight of filling: 2 kilograms
Total weight: 14 kilograms

Fuzing: Nose - Type I
Color and markings:
-Type I: Overall yellow; stenciled in black P30A


-Type II: Overall dark olive green (painted over yellow).  Red paint marks diametrically opposite on shoulders of nose and base.

-Type I: The body consists of a tubular steel cylinder on which the cast-steel nose and base sections are threaded.  A square steel wire, 3/8 inch on the side, is helically wound around the body.  The nose piece is threaded to receive the fuze.  The base has an external recess and extension rod for the tail assembly.  The tail section consists of two sheet-steel plates bent to an angle of 90 degrees and held to the extension rod.  Four pieces of wood, shaped to form a truncated cone, serve as spacers for the fins.  The assembly is held by a steel pressure cap which threads into the extension rod. 

-Type II: The body is one-piece machined steel with the nose threaded to receive the fuze, and the base recessed with an extension rod for the tail assembly.  In all other respects this type is similar to the Type I.
Remarks: Both type resemble the US 30lb Fragmentation Bomb Mk 5 in size and appearance.

24kg G.P.-H.E. Bomb

Overall length: 30.5 inches
Body length: 19.9 inches
Body diameter: 6.4 inches
Tail length: 14.8 inches
Tail width: 6.4 inches
Type of filling: TNT
Weight of filling: 12 kilograms
Total weight: 24 kilograms

Fuzing: Tail only - Type N-1

Color and markings: Overall grey; Nose: red

Description: The bomb is light cased, with a steel body and nose in one piece.  A sheet-metal tail including a sheet-metal strengthening band at the end, is attached to bomb by a metal band which is clamped around the body.  The suspension band is bolted around the body.

Remarks: The bomb was declared obsolete by the Italians before the end of the war.

Next Time: Italian General Purpose/High Explosive Bombs

Monday, 13 June 2016

Imperial Japanese Explosives - Land Mines and Grenades (Part 6)

Imperial Japanese Explosives


Explosive Food Cans

Length: 4 and 1/2 inches
Diameter: 3 and 3/8 inches
Explosive: RDX (78.3%); Mineral Oil (21.7%)
Weight of explosive: 1.37 pounds
Description: Three types of explosive food cans have been recovered, whose main difference lies in the spurious food labels which conceal the true nature of the can. 

The "tin of strawberries" is typical and consists of a standard No.2 can filled with high explosive.  The tin bears a cleverly counterfeited "Libby's Strawberries" label, which covers and conceals the threaded igniter pocket in the side of the can.  This label gives the weight of the can as 1 pound 4 ounces.  The interior of the can is lined with thick brown paper.  Two rectangular metal containers filled with heavy mineral oil are placed in the main filling on either side of the igniter pocket.

Two smaller 14-ounce cans labeled "Libby's Long Slices Fancy Pineapple" and "Del Monte Mixed Salad Vegetables," which are similar to the "Strawberry" can in all respects except size and label, have been recovered.

All the types of charges can be used either as sabotage devices or booby traps depending on the type of initiating system used.  One common initiator has a scratch type igniter, a safety fuse delay (about 1 minute), and a detonator.  Another consists of a brass sleeve containing a scratch type igniter, an integral short delay train, and a detonator.  The third type of igniter consists of a brass sleeve containing a friction pull igniter, and a detonator.  This last igniter has no delay and can be used only if the charge is placed as a booby trap.

Operation: The label of the can is removed or perforated to expose the igniter pocket into which the igniter is threaded.  The activation of the igniter sets off the delay, if present, which fires the detonator and the main charge.

Metal Incendiary Cylinders

Length: 6 and 3/4 inches
Diameter: 2 and 3/4 inches
Incendiary Mixture: Thermite
Description: These cylinders are constructed of a light unidentified metal.  They are filled with thermite and have an igniter located in the center of the top section.

Four types of cylinders have been recovered which differ as to type of casings and igniters.  One casing is a plain cylinder, while the other type has vents around the top to allow more rapid escape of the thermite.  Both casings can be fitted with either a friction pull igniter or a scratch type igniter.

Both igniters are of conventional design and both employ a delay element and a 5-gram first fire charge of antimony sulphide, aluminum, and potassium chlorate.  A circular piece of wood with rough sides is provided as a scratch block for the scratch type igniter.  The block is wrapped in waxed paper and taped to the top of the cylinders in which it is used.

Operation: Place the charge and initiate the igniter.  After the delay time has expired, the first fire charge and then the main incendiary charge are ignited in turn.

Incendiary Brick

Size: Same as standard building brick

Incendiary Mixture: Potassium chlorate, sulphur, ground coal, or sugar, iron fillings, and wax
Description: This device is a skillful imitation of a standard, glazed building brick to which it is comparable in size, weight, and appearance.  The brick is wax coated with paint to give it a realistic finish and so allow it to be carried about without detection.  There is no pocket for insertion of an igniter.

Operation: The incendiary brick is ignited in various ways, all of which are alike in principle.  One method is to pour sulphuric acid and glycerine into a thin rubber tube which is weakened at one point to allow the acid to burn through quickly.  When the acid burns through the tube, it drips onto a small amount of potassium permangenate which ignites the brick.

Incendiary Soap

Length: 4.17 inches
Width: 2.67 inches
Thickness: 1.45 inches
Weight: 14 ounces

Incendiary mixture:
-Barium Nitrate: 30.4%
-Paraffin: 19.4%
-Magnesium: 11.3%
-Aluminum: 11.1%
-Rosin: 10.9%
-Ferrosoferric Oxide: 9.1%
-Nitrocellulose: 4.4%
-Gritty Siliceous Material: 2.6%

Description: This incendiary bar is specifically designed to resemble a bar of "Ivory" soap.  The word "Ivory" is stamped on one side and "Proctor and Gamble" on the other.  The bar burns with an intense flame, but is easily extinguished by water.  It is difficult to ignite.

No method of ignition has been found, but it is probable that some type of ignition device is inserted into the recess in the side of the bar.

40mm Hollow-Charge Rifle Grenade

Overall length: 7.98 inches
Maximum diameter: 1.58 inches

Color: Black and grey

Total weight: 12.45 ounces
Filling: 50/50 RDX and TNT
Weight of filling: 3.81 ounces
Description:  This grenade is a copy of the German Gross Gewehr Panzergranate and is fired from a cup launcher attached to the standard 6.5mm rifle.

The body is cylindrical with a semiconical shaped head.  It is made in two parts threaded together and fitted with a ballistic cap and cone to give the hollow-charge effect.  The forward part contains the explosive charge cast around the cone.  The after part which is made of aluminum has a rifled collar near the base and contains the fuze and explosive train.
The fuze is held in by a base plate with a protruding spigot which is screwed into the base of the grenade.  The fuze is held in position by the spigot.  The needle firing pin is secured in a housing that has a four stirrup-like springs protruding from the side.  Around the housing is a setback spring held in by an arming sleeve which has two sets of grooves notched on the inner side. 

Holding the firing pin stationary is a coil clock spring which is held in by the arming sleeve.  There is also a creep spring between the firing pin and detonator.   The propelling charge consists of a special cartridge with a wooden bullet.
Operation: On firing, setback causes the arming sleeve to move down and it is held down by the stirrup springs which engage in the groove in the arming sleeve.  Centrifugal force then causes the clock spring to expand and the fuze is armed.  On impact the firing pin housing overcomes the creep spring and moves onto the flash cap setting off the detonator and booster.

30mm Hollow-Charge Rifle Grenade

Overall Length: 8 inches
Maximum Diameter: 1 and 5/8 inches

Color: Black and grey

Total Weight: 8.25 ounces
Filling: 50/50 RDX and TNT
Weight of Filling: 1.75 ounces

Description: The explosive head of the 30mm is of the same type construction as that of the 40mm, but on a smaller scale.  The spigots of the 30 and 40mm grenades are identical with the exception of the threads on their forward ends.  Both grenades use the same fuze.

Operation: The operation of the 30mm hollow-charge rifle grenade is identical to that of the 40mm size.

Model 3 Modification 1 Rifle Grenade

Overall Length: 8 inches
Maximum Diameter: 1 and 5/8 inches
Thickness of body wall: 1/8 inch
Length of body: 2 and 13/16 inches
Length of tail: 4 and 5/16 inches
Length of fuze: 1 and 3/16 inches

Color: Black

Filling (main charge): TNT
Weight of Filling: 3 ounces

Description:  This grenade is similar to the Type 99 Kiska grenade with a tail assembly added.  It is designed t be fired from the spigot type rifle grenade launcher.  The body and tail are painted black.

The grenade body is a smooth-surfaced, cylindrical cast steel tube.  It is threaded internally at the forward end to receive the cover plate.  There is a bored opening in the base of the grenade body.  A cylindrical solid steel plug, threaded on its after end to receive the tail assembly, is pressed into this hole.

The tail assembly consists of a stabilizer tube to which four fins are welded.  The tube is constructed of rolled sheet steel with a smooth weld down the joining seam.  Threads are pressed into the forward end to correspond with those on the base plug.  The four fins are of light metal.  The outer end of each fin is doubled back to provide a smooth exposed surface.  The inner edge is bent 90 degrees and provides a surface for spot welding the fin to the tube.  The fins are positioned at 90 degree intervals around the circumference of the tube.

The fuze body differs from the Type 91 and Type 97 hand grenade fuzes only in having an aluminum striker block into which is screwed a steel striker.  A brass shear wire through the block holds the striker away from the percussion cap.

The explosive train of the grenade consists of a percussion cap, black powder relay, cyclonite primer, tetryl booster and a main charge of cast TNT.  The cyclonite is enclosed in a brass container, the tetryl in a cardboard cylinder.  Directly under the tetryl booster there is a setback buffer consisting of a felt washer and a jelly-like pellet.

Operation: Prior to firing the grenade from the rifle the safety fork is withdrawn.  The fuze is fully armed.  On impact the brass wire through the striker block is sheared and the steel striker is driven into the percussion cap.  The resultant flash ignites the black powder relay.

The fuze is instantaneous and cannot be substituted as a fuze for hand grenades.

Remarks: A translation of the labels attached to the stabilizer tube gives the following information: "This grenade can be used on rifles Type 38 and Type 99.  The wooden bullet for Type 38 and Type 99 is to be used."  These two rifles are the standard combat weapons for Japanese troops.

A translation of the tag attached to the safety fork gives the following precautionary measures: "Do not remove fork until ready to fire." and "Do not drop or otherwise strike on the nose."

Smoke Rifle Grenade

Overall Length: 8 and 1/2 inches
Maximum Diameter:
-Body: 2 inches
-Fins: 2 and 9/16 inches

Color: Silver

Total weight: 1.29 pounds
-Hexachlorethane: 56.2%
-Zinc: 27.6%
-Zinc chloride: 2.9%
-Zinc oxide: 13.4%

(The above numbers total 100.1%.  I don't know why.)

Description:  This grenade is used with a special adapter which fits over the end of the rifle barrel.  It is painted silver and thoroughly waterproofed with coats of heavy lacquer and paraffin.

The nose is of No.23 gage B. and X. tin plate with rolled threads to fit those on the body of the grenade.  Soft iron wire is wrapped in the thread groove and soldered in place, presumably to aid in sealing the joint.  The body proper is rolled from No.23 gage B. and X. tin plate and is soldered along one longitudinal seam.  Rolled threads are provided at each end to fit the threads on the nose and base.

The base is stamped from No.18 gage B. and S. sheet steel and is screwed onto the body by means of rolled thread.  Soft iron wire is wrapped and soldered into these thread grooves.  The base is partially filled with plastic which has a threaded hole half filled with solder.  The bottom plate is held in place by a small screw imbedded in the solder.  The igniter pellet is encased in a thin walled brass container which is supported by tin plate screwed and soldered onto the body.

The four smoke ports are placed at 90 degree intervals around the base and are covered with light sheet metal discs which are held in place by waterproof cement covered with paraffin.  There are three flash ports, spaced at 120 degree intervals, in the bottom of the base.

The grenade tube is made of No.18 gage B. and S. seamless steel tubing and the upper end is threaded to fit the small end of the base.  The threaded joint is wrapped with adhesive tape.  The tube is sealed with a paraffin impregnated cardboard disc attached to 9 inches of heavy twine.  The four fins are soldered to, and are equally spaced around, the tube and are of No.24 B. and X. tin plate.

The motive force and primary ignition are furnished by a standard .256 caliber Japanese rifle cartridge loaded with 1.927 grams of powder and fitted with a wood pellet.  This cartridge is wrapped in paper and stored in the grenade tube.

Operation: The rifle cartridge is removed from the grenade tube and inserted into the rifle.  The grenade is placed over the spigot adapter.  When the rifle is fired, the gases from the cartridge propel the grenade and also pass through the flash ports to initiate the igniter pellet which in turn ignites the smoke mixture.  Smoke is then emitted through the emission holes.

Small Incendiary Rifle Grenade

Overall Length: 10 inches
Maximum Diameter: 1 and 7/8 inches

Color: Grey with purple body band

Total weight: 1.01 pounds
Filling: White Phosphorus
Weight of Filling: 42 ounces (Manual states 42 pounds!)
Delay: 4-5 seconds

Description:  This grenade is designed to be launched from a spigot type rifle grenade launcher on the Type 38 or Type 99 Japanese rifle, using a cartridge having a wooden bullet.

The grenade is of light, seamless, steel construction and has an incendiary filling of white phosphorus.  The nose piece is threaded at its forward end to receive the fuze.  A thin, metal well extends into the filler and is soldered around the fuze pocket to give an air tight seal.  This well contains the detonator and auxiliary detonator of the fuze, which serves as the bursting charge for the grenade.

The barrel of the grenade is threaded at its forward end to take the nose piece, and at its after end to receive the hemispherical end plate internally and the base piece externally.  The end plate has a small hole in its center.  The base piece is threaded at one end to screw onto the barrel and at the other end to screw into the stabilizer tube.  A bakelite cushion is cast into the base piece to fit the hemispherical end plate.

The stabilizer consists of a cylindrical tube which threads onto the base piece.  Four fins are welded to the after section of this tube at 90 degree intervals.  The rolled threads, joining the barrel and base piece and base piece and stabilizer, are reinforced by wrapping and soldering soft iron wire into the thread grooves.

The fuze used in this grenade is the same as that used in the Type 97 hand grenade.

Operation:  After the grenade has been placed over the spigot adapter of a rifle loaded with a cartridge having a wooden bullet, the safety pin is removed from the grenade.  When the rifle is fired, the gases from the cartridge propel the grenade, and the force of setback initiates the grenade fuze.  After a short delay, the fuze detonates, rupturing the case of the grenade.

Next Time: Italian and French Explosives

Monday, 6 June 2016

Imperial Japanese Explosives - Land Mines and Grenades (Part 5)

Imperial Japanese Explosives


Incendiary Stick Grenade

Overall length: 13.2 inches
Maximum diameter: 1 and 5/8 inches
Length of handle: 5.3 inches
Filling: Phosphorus, rubber pellets, and carbon disulphide
Description: This grenade body is long and cylindrical with hemispherical ends.  The handle is solid and has a transverse hole drilled through one end.  The body is filled with 41 phosphorus-impregnated rubber pellets in carbon disulphide.  These pellets are scattered by means of a small central bursting charge.  It is possible that the grenade is sometimes filled with a phosphorus smoke filling.  The handle protrudes from one end of the body, the fuze from the body.

The fuze consists of a brass inertia pellet with a steel firing pin separated from the primer by a creep spring.  The inertia weight is held into the fuze by a light brass cap which is crimped into a cannelure in the fuze body so as to prevent the firing pin from reaching the primer.  The firing pin is threaded into the inertia weight, and, before arming, it is not screwed in far enough and its point does not protrude below the base of the inertia weight.

Therefore, before using the grenade it is necessary to screw the firing pin into the inertia weight so that it will protrude.  In addition, a double brass safety pin fits through holes in the brass cap and fuze body into holes in the inertia weight thus preventing the firing pin from reaching the percussion cap.

The delay pellet screws into the base of the fuze and contains a small quantity of granular black powder in the top and a highly pressed pellet of black powder in the lower section.  A hole drilled in the side of the fuze contains a fusible plug which melts when the black powder burns, allowing the escape of the gases formed on combustion of the delay train.  The escape of these gases will enable the thrower to know if the delay pellet has ignited.

Operation: The firing pin must first be threaded down into the inertia weight.  The safety pin is then withdrawn.  Just before throwing, it is necessary to strike the inertia weight on a hard object, driving the striker down into the primer and igniting the delay.  The detonation of the burster tube will scatter the incendiary pellets which will ignite spontaneously.


Molotov Cocktail

Overall length: 11 and 1/4 inches
Maximum diameter: 2 and 1/3 inches
Filling: Any inflammable benzene-type liquid
Capacity: 12 ounces
Description: The body of this grenade consists of a Japanese beer bottle into the top of which is fitted an "all-way" action fuze.  There is a rubber washer under the fuze to render it liquid tight, and the fuze fits into the neck of the bottle in the manner of a crown stopper.

The fuze consists of a firing pin contained in a housing and separated from the detonator contained in a carrier by a safety pin and a creep spring.  The firing pin housing has a hemispherical weight on the top of it and bears against the underside of the nose cap which is of a similar shape.  The bottom of the detonator carrier is also rounded and bears against a cam surface so that it too is free to move.

The safety pin runs through the firing pin housing and rests against the top of the detonator carrier so that neither part is free to move.  Beneath the detonator there is an incendiary mixture consisting of barium nitrate and magnesium.

Operation: The safety pin is pulled out and the grenade is thrown.  On impact the "all-way" fuze will function and set off the detonator thus igniting the incendiary booster and inflammable filler.

Phosphorus-Ignited Molotov Cocktail

Length: 13 and 1/2 inches
Diameter: 3 and 1/2 inches

Length: 9 and 3/4 inches
Diameter: 2 and 1/8 inches

Igniter Capsule
Length: 3/8 inch
Diameter: 2 and 1/8 inches

Grenade (complete): 2 pounds, 12 ounces
Bottle (filled): 1 pound, 10.5 ounces
Inflammable liquid: 9.5 ounces
Igniter capsule (complete): 2 ounces
Igniter compound (black phosphorus): 1 ounce

Filling: 15 percent solution of polymethylmethacrylate in benzene
Description: The grenade consists of a 300 cc green or clear glass bottle filled with an inflammable liquid and sealed with an ordinary crown type cap.  The bottle is fitted with an adjustable rubber harness which is used to hold a flat circular glass igniter capsule to the base.

The grenade is packed in a tubular varnished cardboard carton.  The igniter capsule is well protected in the container by several layers of cardboard and sawdust.

Operation: A rip cord is pulled to open the carton.  The igniter capsule is secured to the base of the bottle by the rubber harness.  When the grenade is thrown forcible against a hard target it shatters and the friction between the pieces of phosphorus causes instant ignition of the inflammable material.  The viscous nature of the filling prevents undue splashing and insures adherence to the target.

Frangible HCN Grenades

Maximum diameter: 3.9 inches

Total Weight: 1.2 pounds
Filling: Hydrocyanic acid
Weight of filling: 12.2 fluid ounces
Capacity: 14.5 fluid ounces

Description: These grenades are recognizable mainly as round glass bowls filled with HCN.

They differ in minor details:
1. The copper stabilized type is round bottom whereas the 172 B-K and 172 C-K have flat bottoms.

2. The copper gives one a yellow tint while the other two appear to be light green.

3. The copper stabilized type has one moulded ring around the outside instead of two.

4. The copper stabilized type is closed by a crown cap over a cork stopper and the other two are closed by a crown cap over a rubber washer.

5. The copper stabilized type is carried in a sheet metal container and the 172 B-K and 172 C-K are carried in cardboard containers.

The grenades contain 12.2 oz. of liquid which is about 80% Hydrocyanic acid.   This is a very strong systemic poison.

Operation: The grenade is thrown and on impact the glass will break releasing the HCN.  This gas is swift and deadly if inhaled.  In such quantities the gas is exceptionally nonpersistent so these grenades are designed for use in small closed spaces such as pillboxes and tanks.

Frangible Smoke Grenade

Overall length: 3.3 inches
Maximum diameter: 2.6 inches
Circumference: 9.3 inches
Color: Light Yellow
Total weight: 9.7 ounces
Filling: Titanium and silicon tetrachloride
Weight of filling: 4.1 ounces
Description:  This grenade is a flat bottom spherical container made of clear glass.  It has a short neck closed by a red rubber stopper held under a red rubber washer within an inner iron crown cap, this being enclosed by a heavier iron outer crown cap.

The filling is a mixture of titanium and silicon tetrachloride which will be hydrolyzed by the moisture of the air, with the formation of hydroxides and hydrochloric acid.
Operation: The grenade is thrown and on impact the glass bottle breaks releasing the fluid and producing smoke.  It is intended for use in screening operations.  Though the filler is irritating to the skin as a liquid, in ordinary field concentrations the smoke is hardly irritating enough to cause coughing.

Explosive Toothpaste Tube

Length: 6.87 inches
Width: 2 inches (approximately)

Explosive: RDX (80.2%); mineral oil and wax (19.8%)
Weight of explosive: 4.23 ounces

Description: The "Tube of Toothpaste" is an unpainted, tin tube which contains an explosive filling and takes a separately packed ignition device.  The tube is closed by a screwed cap.

The ignition device consists primarily of a brass plug which contains a match composition, a brass tube housing the black powder delay train, and a brass detonator tube filled with mercury fulminate over tetryl.

The brass plug is threaded externally to receive a safety cap, and internally at the opposite end to take the delay tube.  The detonator is crimped into the delay tube.

Operation: Remove the screw cap from the tube, insert the igniting device, remove the safety cap, and strike the match composition against a rough surface.

Explosive Coal

Length: 3 inches (approximately)
Width: 2 inches (approximately)

Explosive: RDX
Color: Black

Description:  These devices consist of thin earthenware containers of irregular sizes and shapes coated with a bitumen type of paint to give them the appearance of anthracite coal.  Each container if filled with explosive and contains an igniter.  The igniter is a copper tube with a detonator at one end and a small black powder charge at the other end placed next to the container wall.

Close examination of a single piece of explosive will identification, but it is virtually impossible to detect when mixed with real coal.

Operation: When exposed to fire, the heat eventually ignites the black powder which in turn sets off the detonator and main charge.

Next Time: More Imperial Japanese Sabotage Devices, and Rifle Grenades