Monday, 4 December 2017

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

-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

-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

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