OP 1664 - U.S. Explosive Ordnance (Vol. 1); Part 1 - Projectiles, Propellants, and Projectile Fuzes; Chapter 1 - Projectiles; Section 12 - 40-mm Projectiles: 40-mm A.A. H.E.-I. (a) Mk 1 Mods 1 - 24 and (b) Mk 2 Mods 1

U.S. EXPLOSIVE ORDNANCE

PART 1 - PROJECTILES, PROPELLANT,
AND PROECTILE FUZES

Chapter 1 - Projectiles

Section 12 - 40-mm PROJECTILES

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

(May have "Dark" or "Dark Ignition" tracer.)

Over-all length, inches
With nose fuze	7.1
Without nose fuze	5.2
Diameter of base, inches	1.3
Distance base to band, inches	(a) 1.675 (b) 1.730
Width of band, inch	0.6
Diameter at bourrelet, inch	1.57
Filling	H.E.: Cast TNT H.E.-I.: Cast TNT and Incendiary
Weight of filling, pound	(a) 0.148 (b) 0.150
Weight of loaded projectile, pound	1.985
Charge/weight ratio	5.0%
Cartridge Case	Mk 1, Mk 2, Mk 3
Primer	Mk 21 Mods 2 and 3; Mk 22 Mods 0 and 1
Tracer	Mk 10, Mk 11
Fuzes	Nose - Mk 27 Mods 0 and 1

See Tracer Mk 11 for "Dark" and "Dark Ignition" developments.

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

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.

Identification - Marking and Painting

Color
Type	Body	Band	Tip	Remarks
H.E.-P.	Green	Green	Green	Plug in tracer
H.E.-T./S.D.	Green	White	Green
H.E./S.D.	Green	Black	Green	Non-luminous tracer
H.E.-I.-T./S.D.	Green	White	Red
H.E.-I.-P.	Green	Red	Red	Plug in base
H.E.-I./S.D.	Green	Black	red	Non-luminous tracer
H.E.-I.-T.	Green	White	Red	S.D. relay not loaded
	with black
	band
B.L. & T.	Red	White	red	Dummy fuze
B.L. & P.	Red	Red	red	Dummy fuze and plug in base

Figure 76. 40-mm Projectiles.