Monday 11 December 2017

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

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