American Projectiles and Explosives - Army Developmental Rockets

American Projectiles and Explosives

Army Developmental Rockets

2.36-inch Smoke T-27E1

No picture available

Overall length: 16.1 inches
Total weight: 3.4 pounds
Head length: 4.5 inches
H.C. smoke charge: 1 pound


General: This rocket is generally similar to the other smoke rockets in this series, differing mainly in its payload.  It also differs in that it has a circle of smoke ports in the base of the head, which allows the H.C. smoke to be blown out of the head on impact.  Pressure of the H.C. smoke blows out the port covers after the base fuze sets off the H.C. gas.  The H.C. smoke will issue for one minute after impact.






2.36-inch Incendiary T3

No picture available

Overall length: 17.7 inches
Total weight: 3.4 pounds
Head length: 4.1 inches
Thermite filler: 1.1 pounds



General: The T31 is like the other 2.36-inch chemical load rockets, using the same motor and fuzing as the M10.  It has, however, a mmuch shorter head.  On impact, it ignites and burns, producing extreme heat.  It is currently issued for practice only.








4.5-inch H.E. S.S. T22 and Practice T46

No picture available

General: These rockets have the heavier shell of the M8A2 and M9A2.  Also, the motor tube is further strengthened and the assembly of the fins slightly changed.  The igniter is loaded in a tube attached to the trap, extending the length of the propellant charge.  Its safe temperature range: -20 to +120 degrees Fahrenheit.







3.5-inch A/T T80 and Practice T85

Overall length: 26.3 inches
Weight of head: 5.11 pounds
65/35 Cyclotal charge: 1.82 pounds
Length of motor: 15.6 inches

Fuzing: T160E1


General: This design is mainly a larger type of the 2.36-inch A/T model, with improvements.  It has the shaped-charge explosive for penetration.  It also has a more efficient propellant and an all-ways-action fuze.  Performance tests are still being conducted.  It is the largest of the shoulder-fired rockets.


Propellant: There are 12 sticks of powder five inches long and 0.375 inches in diameter; total weight, 160 grams.  The igniter is conventional.








4.5-inch H.E. A.R. T83 and Practice T87

Overall length: 75.88 inches
Total weight: 98 pounds
Head length: 16.68 inches
Weight of charge: 8.8 pounds
Range: 1,500 yards

Fuzing: Mk 149


General: This is one of the "fixed-fin" type of 4.5-inch rockets, the other being the S.A.P. round.  It is a high-velocity rocket, fired from the zero-length launchers.


Head: The high-explosive head T2002 is thin-walled and has an adapter and fuze-seat liner for the Nose Fuze Mk 149.  An Auxiliary Booster Mk 3 Mod 1 is shipped in the fuze seat, protected by a chipboard disc and a shipping plug.


Motor: The T2000 motor is connected to the head by a steel coupling, threaded internally.  The motor tube is constricted at the rear to form the nozzle.  Lug bands are one button-type band and one zero-length band, 45.53 inches and 10.25 inches respectively, from the base of the rocket.


Tail: The T2000 tail assembly, four flat fins mounted radially on a metal sleeve, is secured to the nozzle by a threaded retainer coupling.


Propellant: Twelve single-perforated sticks of powder having 7/16-inches inside diameter and 1.22 inches outside diameter, 20.6 inches long, are mounted in two banks of six each on the bars of a cage-like support.


Igniter: An electric squib and 2 and 3/4 ounces of black powder are assembled in a plastic tube 6 and 3/4 inches long and one inch in diameter.   This tube is suspended from the end of the propellant in the center of the tube.  The ignition wires pass to the rear through a plastic closing cap cemented in the throat of the nozzle.  They terminate in a phone-type plug.  About two feet of igniter cable are held in the flare of the nozzle by a fiber cap cemented in place.


Practice Round: The T87 - T2003 head and T2000 motor - is like the T83 except for the live fuze and explosives, for which inert substitutes are provided.







4.5-inch S.A.P. A.R. T78 and Practice T86

No picture available

Overall length: 70.89 inches
Total weight: 98 pounds
Head length: 15 inches
Weight of charge: 2.8 pounds
Range: 1,500 yards

Fuzing: T156


General: This is another "fixed-fin" 4.5-inch rocket.  A high-velocity aircraft rocket, it is fired from the zero-length launchers.


Head: This S.A.P. Head T2000 is of heavy-walled construction and threaded at the base to receive the motor tube.


Motor: This round uses the same motor and fin assembly as are found on the T83 round.  It also uses the same propellant and igniter.  The Practice Round T86, T2001 Head, is inert fuzed and loaded.

4.5-inch H.E. S.S. T160 and Practice T161

Overall length (w/o fuze): 30.07 inches
TNT charge: 6 pounds

Fuzing: M81 or M402 (V.T.)


General: Because of its more efficient propellant, this round is expected to be a more powerful, longer-range rocket.  Except for the propellant, it is of conventional Army design.


Propellant: Seven cylindrical powder sticks, 13.5 inches long and 1.35 inches in diameter, furnish the power.  The grid type of support is used instead of the conventional trap, and the igniter is housed against the motor wall, instead of being placed in the center.  Safe temperature limits for this round are from -20 to +120 degrees Fahrenheit.

7.2-inch H.E. T24

See Navy 7.2-inch chemical warfare rocket

7.2-inch D.R. T37 and T88

See Navy 7.2-inch demolition rocket

8-inch D.R. T25

No picture available

Overall length: 60.25 inches

Total weight: 137 pounds

Head length: 27.5 inches

Filler: TNT or 50/50 Amatol

Weight of filler: 58 pounds

Range: 550 yards

Fuzing: T20

General: This round is a modified 100-pound G.P. bomb fastened to a 4.5-inch rocket motor.

Construction: Suspension lugs and base plug are removed from the standard 100-pound bomb, and a motor adapter substituted for the base plug.  The motor is the standard type for the 4.5-inch Army folding-fin type of rocket, modified to take the special box-type fin.  The fuze seat in the bomb is modified to receive the Point Detonating Fuze T20.

Launcher: The metal crate in which the round is shipped serves as an expendable launcher.

H.E. S.S. 21-cm T36 and Practice T45

Overall length: 48.86 inches
Total weight: 91.75 pounds

Fuzing: M51 (M81)


General: This round is a copy of the German rocket of the same type.  At present, performance tests are being conducted by the Army Ordnance Department.  It is of conventional structure, with the artillery-type fuze.

Next Time: Rocket Bodies, and Navy Rockets (Part 1)

American Projectiles and Explosives - Rocket Projectiles

American Projectiles and Explosives

Army Rockets

2.36-inch A/T

Service: M6A1, M6A3, M6A4, M6A5

Practice: M7A1, M7A3, M7A4, M7A6

  

M6A1 and M6A3 Data

Overall length: 21.6 inches
Total weight: M6A1 - 3.4 pounds; M6A3 - 19.4 pounds
Head length: 8.6 inches
Body length: 4.11 inches
Body diameter: 2.23 inches
Body wall thickness: 0.087 inches

Ogive length:
-M6A3 (Cone-Shaped): 4.5 inches
-M6A3 (Hemispherical): 4.56 inches

Ogive diameter (at flange): 2.245 inches
Motor tube length: 6.32 inches
Motor tube (inner diameter): 1.06 inches
Motor tube wall thickness: 0.095 inches

Maximum range: 700 yards
Effective range: 300 yards
Muzzle velocity: 265 feet/sec

Color: Olive drab

Explosive: Pentolite


General: Pill boxes, tanks, and armored vehicles are prime targets.  The rocket can also be used in a stationary emplacement for demolition or as an anti-tank mine or a booby trap.  The rocket can penetrate three inches of homogeneous steel armor plate at all ranges and at angles of impact as low as 30 degrees, employing the shaped-charge explosive.


Launcher: The Rocket Launcher M1A1, commonly called the "bazooka", is an electrically operated weapon of the open-tube type, fired from the shoulder, and weighing 13.26 pounds.  Rocket Launcher M9A1 is similar but breaks down into two sections, each 31 inches long, for ease in transporting.


Construction: The 2.36-inch A/T Rockets M6A1 and M6A3 are identical except for difference in the ogive and the tail assembly.  In other respects the two rockets are similar, consisting of a hollow ogive crimped onto the body, a body union fitting into the base of the body with internal threads to receive the motor, and a fuze which is located in the forward end of the motor tube.  The M6A1 has a conical ogive, whereas the M6A3 has a hemispherical ogive which gives better penetration by forming a stronger stand-off piece for the shaped-charged effect of the explosive.  M6A4 is like the M6A3, except that it is lighter, being made of high-strength alloys, and also uses the Bore-Safe Fuze M400.  The M6A5 uses the Bore-Safe Fuze M401 and has a larger propellant grain, which eliminates the safety disk.


Tail Assembly:  The M6A1 has six fins (5 and 1/2 inches long) spot-welded to the nozzle, a steel cup internally threaded at the forward end to screw onto the motor tube.  The M6A3 has a different type of tail assembly to obtain fin area and counteract the change of the center of gravity effected by the hemispherical nose.  This tail assembly consists of four sheet-steel fins 2 and 5/16 inches long, each of which is curved over an arc of 90 degrees on its outboard edge to form a blade.  Each fin is joined to the other by welding, with an overlap of approximately a 1/2 inch to form a circular drum which is actually nothing more than a continuation of the four fins.  The bases of the fins are spot-welded to the nozzle.  In the M6A5 and M7A6 the free end of the ignition wire is attached to the shroud tail by a chip-board disk, instead of the tape on earlier models.


Propellant: The propellant consists of five sticks of ballistite.  On an average, the propellant weighs approximately 61 and 1/2 grams, though it is loaded not by weight but rather by length of powder stick, to keep the pressure for various rounds at a relatively constant value.  The M6A4 and M6A5 use the Powder M7, which burns at a lower temperature, +120 to -40 degrees Fahrenheit.


Fuze: The fuze for the M6A1 and M6A3 consists of a steel firing pin which slips into the central cavity of the fuze body, where it is held in a rearward position by the firing pin spring.  A circumferential groove midway down the length of the firing pin receives the safety pin, which extends through the motor tube.  When the safety pin is removed, the firing pin is free to move forward, restrained only by the action of the firing pin spring.  After the safety pin has been removed, the firing pin will overcome the spring and detonate the rocket if it is dropped over four feet.  The fuze body contains the Detonator M18 of lead azide and tetryl, and the booster charge of tetryl.


Remarks: The practice rounds are similar to their accompanying service rounds, except that they are inert-loaded and have a dummy fuze or steel weight to fill the empty fuze space.

The M6A5 and M7A6 have plastic closing plugs, making them waterproof rounds.  They also use the Powder M7, which burns at a lower temperature, +120 to -40 degrees Faherenheit.

The M6A1 and M7A1 are now considered obsolete.









2.36-inch Smoke (W.P.) M10, M10A1, M10A2, M10A3

M10 Data

Overall length: 17.1 inches
Total weight: 3.4 pounds
Head length: 5 and 1/2 inches
Head diameter: 2.3 inches
Maximum diameter: 2.36 inches

W.P. charge: 405 grams
Burster charge: 4 grams
Effective range: 300 yards

Color:
-Motor: Olive drab
-Head: Blue grey



General: This rocket is designed not only as a screening agent, but also to cause casualties.  White phosphorus in smoke form has little effect upon the human body, but particles cause small burns.  This rocket makes an effective weapon for dislodging enemy troops from dug-outs and foxholes.


Launcher: The 2.36-inch Smoke Rocket M10 is fired from the Launcher M1A1 or M9, the "bazooka".


Construction: The components of this rocket are the motor and the head assembly.  The motor presently used is the M6A1, which is being replaced by the M6A3.  As new motors are developed, it is contemplated that this rocket will be modified.

The head assembly consists of a container for the smoke charge with a long burster well containing PETN inserted from its after end.  A collar is soldered to the base of the container.  The spacer slips over the threads of the collar and is held against the flat surfaces of the collar by the fuze body, forming a joint between the two.  The primer holder is threaded into the fuze body.


Tail Assembly:  The 2.36-inch Smoke Rocket M10 has the standard tail assembly for this M6A1 or M6A3 motors.


Fuze: The fuze is similar to that used in the A/T Rocket M6A3.


Remarks: The M10A1 and M10A2 differ from the M10 in the type of propellant used.  The M10A1 used the T1E1 Salted Powder, with a temperature range of 120 to -20 degrees Fahrenheit.  The M10A2 uses the Powder M7, 120 to -40 degrees Fahrenheit.  The M10A3 differs from the M10A2 in that it uses the Fuze M401.










3.25-inch Target M2, M2A1, M2A2

Overall length: 59 inches
Width across fins: 24 inches
Weight: 37.5 pounds
Propellant weight: 3.2 inches

Range: 1,700 yards
Maximum velocity: 530 feet/sec
Burning time of flare: 30 seconds


General: This is a high-speed target for firing practice with automatic A.A. weapons.


Propellant: The propellant has grains five inches long and 7/8-inch in diameter, with a 5/16-inch axial hole.  It is ignited by an electric squib.


M2A1: When a flare is added to the 3.25-inch Target Rocket M2 for anti-aircraft target practice at night, the resulting projectile is designated as the M2A1.  The flare burns for 30 seconds from the beginning of flight.


M2A2: This design has a flat nose, to which is threaded a yellow flare for both day and night tracking.  It also has a different system for igniter contact: the lead wires pass in turn through the nozzle and an inner fiber closing cup and connect to a household-type service plug, which is held by an outer fiber-board closing cup.  There are 18 inches of igniter cable coiled between the closing cups, to allow ample lead for connecting to the launcher.








4.5-inch H.E. M8, M8A1, M8A2, and M8A3; also Practice M9, M9A1, M9A2, and M9A3

Overall length: 33 inches
Total weight: 38 pounds
Head length: 7.5 inches
Wall thickness: 0.2 inches

Burster tube length: 15.5 inches
Fin length: 4 and 1/3 inches
Bursting charge weight (TNT): 4.3 pounds
Maximum range: 4,500 yards
Muzzle velocity: 840 feet/sec

Fuzing: M4, M4A1, M4A2


General: The initial issue of the rocket went to the Army Air Forces for projection from aircraft launchers against ground targets; but, in-asmuch as the rocket was originally designed for use from ground launchers, its use in aircraft has been discontinued.


Construction: The head is a thin-walled high-capacity type, rounded at the nose to form the ogive, threaded at the nose to take the fuze adapter, and threaded externally aft to fit into the motor.  A burster tube is fitted to the head and extends down into the motor, a design which utilizes the motor tube for additional fragments, since the burster tube as well as the head itself is loaded with TNT.

The motor is a steel tube of uniform diameter except at the after end, where it constricts and then flares to form the nozzle.  The motor houses the trap assembly, which consists of ten wires running from the trap plate on the forward end to the trap ring on the after end.  The trap assembly holds the thirty sticks of propellant and fits around the burster tube.  The motor tube is threaded internally forward to take the head, and just abaft this thread is a groove which weakens the tube to provide a safety shear point, should the motor pressure become too great.

The fin assembly for the rocket opens and guides the rocket in flight only after the rocket has cleared the launcher.  The fins of the assembly are held in place by the fin retainer, which is expelled by the blast of the escaping gas.  After clearing the launcher, the fins snap to their outstretched position.  There are six fins.

The M8A1 involved a change in the design of the motor tube to strengthen it on the threaded end.  The head of the M8 was used by machining new base threads.  Tests on the M8A1 indicated that the base of the modified head was weak, and a new head was designed for use with the motor of the M8A1.  This rocket, the M8A2, will suspersede the M8 and M8A1.  The M8A3 is a modification of the M8A2 made by the addition of a locking burr to each fin blade to assist in rigidly maintaining the fin in full open position during flight.


Propellant: The propellant consists of 30 sticks of ballistite.  Each stick is five inches long and 7/8-inch in diameter with a 1/4-inch axial hole.  Three sticks are placed on each trap wire, and there is sufficient clearance between the sticks and the wire to allow burning of the inner stick wall simultaneously with the burning of the outer wall.  Two igniter-bag assemblies are bound on two opposite columns of the propellant.  The bags assist the ignition of the propellant by catching the flame of the igniter and, in turn, igniting the upper propellant sticks.


Practice Rockets M9, M9A1, M9A2, M9A3: These rockets are similar in design and construction to the M8 series, lacking only the explosive charge and live fuze.  The Fuze M4 and booster may be assembled and used in the M9 as a spotting charge.









4.5-inch H.E. S.S. M16, M16E1, and M16E2; Practice M17, M17E1, and M17E2; M20 and M21

M16 Data

Overall length: 31 inches
Total weight: 42.5 pounds
Head length (w/ burster tube): 23.29 inches


TNT charge: 4.3 pounds
Maximum range: 5,250 yards
Muzzle velocity: 830 feet/sec

Fuzing: M81


Description: The head, loaded with high explosive, contains a fuze-well cup and a burster tube.  The burster tube projects about 15 inches into the center of the rocket motor to secure additional fragmentation.  The motor body is a steel tube threaded at each end to receive the head and the nozzle plate, which contains eight nozzles equally spaced in a circle and one nozzle in the center.  The eight nozzles are set at an angle in order to impart rotation to the round when fired.  The center nozzle is normally closed by a blowout disc which is designed to fail when the internal pressure in the body surpasses a predetermined limit.  The nozzle openings are protected by a plastic sealing disc which remains in place during firing and is blown out by the rocket blast.


Propellant: The propelling charge consists of 30 grains of ballistite strung on wires of a cage-like trap.  The igniter consists of a charge of black powder enclosed in a plastic tube attached to the trap and running the length of the charge.  The tube also contains an electric squib.  The leads of the squib pass through one of the nozzles, one lead being ground to the motor body and the other connected to a contact ring.


M20: The M20 is similar in design and construction to the M16, differing only in that the ignition wires are attached to spools rather than contact rings.


Practice Rockets M17 and M21: These are similar in design and construction to the H.E. rounds, but lack the explosive charge and the live fuze.

The M16E1 has a deeper fuze cavity for the V.T. Fuze M402 (Mk 173).  Shipped with these rockets is a supplementary charge to fill part of this cavity in case the Fuzes M81 or M48A2 are used.

The M16E2 is like the M16E1, except that purge pellets of 411E composition have been added to eliminate chunks in burning.








5-inch A.R.

No picture available

The Army is currently using the Navy-designed 5-inch aircraft rockets.

7.2-inch Chemical M25 and M27

No picture available

In the 7.2-inch size, the Army has standardized the chemical round designed by the Navy.

Next Time: Army Developmental Types

American Projectiles and Explosives - 1.1-inch, 7.2-inch, and "Pounder" Projectiles

American Projectiles and Explosives

1.1-Inch Projectiles

1.1-inch A.A.(a) Mk 1 Mods 0-28, (b) Mk S.D. 1

Overall length w/ nose fuze: 5.8 inches
Overall length w/o nose fuze: 4.1 inches
Diameter of base: 1.085 inches
Distance base to band: 0.87 inches
Width of band: 1 inch
Diameter at bourrelet: 1.095 inches

Filling: Explosive D

Weight of filling:
-(a) 0.037 pounds
-(b) 0.034 pounds

Weight of loaded projectile: 0.917 pounds
Charge/Weight ratio: 4%

Cartridge case: Mk 1

Primer: Mk 19 and Mods 1, 2, and 3

Tracer: Divided into two increments and pressed into the recess by hydraulic pressure, the tracer is ignited by the propellant charge from the cartridge case.

Fuzes:
-Nose: Modified Mk 12 Mods 2 and 3 (P.D.F.)
-Mk 34 and all Mods (P.D.F.)


The 1.1-inch A.A. gun is not being further developed in the Navy.

The 1.1-inch Mk 1 is not self-destroying; the primary difference between the two projectiles.

The Mk S.D. 1 consists of a Mk 1 projectile body modified for self-destruction by drilling through the wall between the tracer and H.E. cavities.

The Mk 1 projectile may also be issued B.L. & T. for target practice or de-icing.

The 28 Mods are to distinguish among contractors.







1.1-inch A.A. Mk 2 Mods 0 and 1

Overall length w/ nose fuze: 5.7 inches
Overall length w/o nose fuze: 4.1 inches
Diameter of base: 1.085 inches
Distance base to band: 0.87 inches
Width of band: 1 inch
Diameter at bourrelet: 1.095 inches

Filling: Explosive D

Weight of filling: 0.034 pounds
Weight of loaded projectile: 0.917 pounds
Charge/Weight ratio: 3.7%

Cartridge case: Mk 1

Primer: Mk 19 and Mods 1, 2, and 3

Tracer: Divided into two increments and pressed into the recess by hydraulic pressure, the tracer is ignited by the propellant charge from the cartridge case.

Fuzes:
-Nose: Modified Mk 12 Mods 2 and 3 (P.D.F.)
-Mk 34 and all Mods (P.D.F.)


The Mk 2 has a self-destroying tracer.

"Pounder" Projectiles

1-pounder Common Mk 2 Mods 0 and 1

Guns used in: 1-pdr/40

Overall length: 3.56 inches
Diameter of base: 1.441 inches
Distance base to band: 0.829 inches
Width of band: 0.731 inches
Diameter at bourrelet: 1.445 inches

Filling: Black Powder

Weight of filling: 0.026 pounds
Weight of loaded projectile: 1.088 pounds
Charge/Weight ratio: 2.07%

Cartridge case: Mk 2
Primer: Mk 10 Mod 9
 Tracer: Integral
Fuzes: Base: Mk 8 Mod 4 (B.I.F.)



This ammunition is used in coast guard guns.  Their bursting charge is black powder and TNT, or black powder alone.  This should be kept in mind when unscrewing the fuze, as some of the powder may have fallen down into the threads and the friction would cause detonation.

The Primer Mk 10 Mod 8 may be used for saluting charges only.

Base Fuzes Mk 2 Mod 9 and Mk 8 Mod 5, without tracers, may be used, but the Mk 8 Mod 4 is the preferred assembly.

This round may be issued B.L. & P. for target practice.










3-pounder Common Mk 4 Mod 1

Guns used in: 3-pdr/50

Overall length: 6.681 inches
Diameter of base: 1.75 inches
Distance base to band: 1.185 inches
Width of band: 0.787 inches
Diameter at bourrelet: 1.845 inches

Filling: Black Powder and TNT

Weight of filling: 0.13 pounds
Weight of loaded projectile: 3.3 pounds
Charge/Weight ratio: 3.93%

Cartridge case: Mk 1
Primer: Mk 10 Mod 9
 Tracer: Integral
Fuzes: Base: Mk 8 Mod 4 (B.I.F.)


Fuzes Mk 8 Mod 5 and Mk 2 Mod 9, without tracers, may be used; but the Fuze Mk 8 Mod 4 is the preferred assembly.  See other notes on 1-pounder Common.









6-pounder Common Mk 3 Mods 3 and 4

Guns used in: 6-pdr/40, /42, /45, /50

Overall length: 8.45 inches
Diameter of base: 2.224 inches
Distance base to band: 1.493 inches
Width of band: 0.787 inches
Diameter at bourrelet: 2.239 inches

Filling: Black Powder and TNT

Weight of filling: 0.24 pounds
Weight of loaded projectile: N/A
Charge/Weight ratio: 4%

Cartridge case: Mk 1
Primer: Mk 10 Mod 9
 Tracer: Integral
Fuzes: Base: Mk 8 Mod 4 (B.I.F.)


This round may be issued B.L. & P. or B.L. & T. with the Tracer Mk 7 for target practice.  See other notes on 1-pounder Common.







6-pounder Common Mk 5 Mods 0 and 3

Guns used in: 6-pdr/40, /42, /45, /50

Overall length: 8.26 inches
Diameter of base: 2.22 inches
Distance base to band: 1.493 inches
Width of band: 0.787 inches
Diameter at bourrelet: 2.237 inches

Filling: Black Powder and TNT

Weight of filling: 0.23 pounds
Weight of loaded projectile: 6 pounds
Charge/Weight ratio: 4%

Cartridge case: Mk 1
Primer: Mk 10 Mod 9
 Tracer: Integral
Fuzes: Base: Mk 8 Mod 4 (B.I.F.)


See notes on 6-pounder Common Projectile Mk 3.










7.2-inch Projectile

7.2-inch Projector Charge "Hedgehog"

Overall length: 38.6 inches
Head length: 19 inches
Head diameter: 7.2 inches
Head weight: 17.9 pounds

TNT filler: 31.1 pounds
Wall thickness: 0.2 inches
Tail tube diameter: 1.75 inches
Tail width: 7 inches



General: The projectile consists of a flat-nosed head with a conical tail fairing and parallel sides.  The adapter and fuze thread into the nose.  The motor unit consists of a smokeless powder cartridge with primer, which is lodged forward in the tail tube, the tube fitting over a firing post.  The primer is detonated by electric contacts in the post.  This charge is for use on Projectors Mk 10 and Mk 11.

The tail is a steel tube attached to the head by a threaded joint.  Tail fins have a 10-degree twist and are attached with a drum support to give a slow rotation and stabilized trajectory.


Remarks: When Torpex is used, the weight is increased by approximately 2.5 pounds.

The above data are based on the 7.2-inch Head Mk 4A and the 1.75-inch P.C. Tail Mk 4A.  These are being replaced by the 7.2-inch Head Mk 4 Mod 0 and the 1.75-inch P.C. Tail Mk 6 Mod 0

Nose Fuzes Mk 136 and Mk 140 are replaced by the Nose Fuze Mk 158

Next Time: Rocket Projectiles

American Projectiles and Explosives - 40mm Projectiles

American Projectiles and Explosives

40mm Projectiles

40mm A.A. H.E.I. (a) Mk 1 Mods 1-24 and (b) Mk 2 Mods 1-35

Overall length w/ nose fuze: 7.1 inches
Overall length w/o nose fuze: 5.2 inches
Diameter of base: 1.3 inches
Distance base to band: (a) 1.675 inches; (b) 1.73 inches
Width of band: 0.6 inches
Diameter at bourrelet: 1.57 inches

Filling:
-H.E.: Cast TNT
-H.E.I.: Cast TNT and Incendiary

Weight of filling:
-(a) 0.148 pounds
-(b) 0.15 pounds

Weight of loaded projectile: 1.985 pounds
Charge/Weight ratio: 5%

Cartridge case: Mk 1, 2, 3

Primer: M21 Mods 2 and 3; Mk 22 Mods 0 and 1

Tracer: Mk 10, Mk 11

Fuzes:
-Nose: Mk 27 Mods 0 and 1


The Mk 1 and the Mk 2 projectiles are both loaded H.E. in three increments.  The Mk 2 may also be loaded H.E.I. with the central increment as incendiary composition.  The Mk 2 H.E.I. round may be plugged instead of tracered.  Both projectile bodies may be issued B.L. & P. or B.L. & T. for target practice or de-icing.

Tracer Mk 10 has been declared unserviceable and is being replaced by the Tracer Mk 11 in all assemblies.

The 24 Mods of Mk 1 and the 35 Mods of Mk 2 are merely bookkeeping designations.

40mm Mk 3

Except for some minor differences in dimensions, the main difference between the Mk 3 projectile and the Mks 1 and 2 is that there is no hole in the base of the Mk 3 for a tracer or plug.  This design was developed when the tactical need for non-trace ammunition arose; but with the appearance of "Dark" tracers, the Mk 3 projectile's original purpose was eliminated.





 40mm A.A. M81A1 A.P. and A.P.T.

Overall length : 6.19 inches
Diameter of base: 1.55 inches
Distance base to band: 0.803 inches
Width of band: 0.64 inches
Diameter at bourrelet: 1.55 inches

Filling: N/A
Weight of loaded projectile: 1.96 pounds
Charge/Weight ratio: N/A

Cartridge case: Mk 1, 2, or 3
Primer: Mk 21, Mk 22
Tracer: Integral

Fuzes: None


This projectile is an Army design manufactured for the Navy to Naval specifications.

The A.P. round has a plug in the tracer cavity; the A.P.T. has a red tracer.

Next Time: 1.1-inch, 7.2-inch, and "Pounder" Projectiles