Monday, 1 June 2015

Imperial Japanese Army Ammunition - 37mm Projectiles

Japanese Explosive Ordnance: Army and Navy Ammunition



We start seeing more aircraft cannon rounds, specifically some of the larger calibers used on IJ aircraft. Since we're still in the Army portion, it's safe to assume that the guns mentioned are the ones used in the Ki-45 and Ki-46 (variant depending).

37mm High Explosive Incendiary Projectile




Overall length of projectile: 89mm (without fuze)
Length of complete round: 197mm (fuzed)
Diameter at bourrelet: 37mm
Width of rotating band: 10mm
Weight of projectile filled: 436.2g
Filling: Cyclonite and incendiary mixture

Used in: Ho-203 aircraft cannon

Case:
-Length: 111.5mm
-Diameter at base: 47mm
-Weight (Empty): 226.5g
-Remarks: The case is comparatively short, made of brass, and is slightly necked.

Propellant: Graphited smokeless powder in flat 4mm squares poured loosely into the case and sealed in with a cardboard disc. The weight of the propellant is 59.8g.
Color and Markings: Black body, red nose band, yellow body band.

Characters stenciled on body: (Ho 203)


Fuzing: Type 100 small instantaneous fuze.

Remarks:
This projectile is constructed in two pieces. It has a nearly straight-sided main body and an ogival-shaped nose piece which threads into the main body. The main charge is cyclonite and an incendiary mixture. The incendiary mixture is pressed into the base of the cavity, with the cyclonite filling the remained of the cavity and the nose piece. There is also an empty practice projectile similar in appearance to the H.E.I. but having the nose piece and dummy fuze constructed in one piece. The projectile is painted black overall.

Characters stenciled on practice shell body: (Ho 203)


and (Ma 438)



37mm High Explosive Incendiary Projectile




Overall length of projectile: 89mm (without fuze)
Length of complete round: 246mm
Diameter at bourrelet: 37mm
Width of rotating band: 10mm
Weight of projectile empty: 398.3g
Filling: Mixture of cyclonite and wax and incendiary composition

Used in: Ho 204 aircraft cannon

Case:
-Length: 144mm
-Diameter at base: 43.5mm
-Weight (empty): 381.2g
-Remarks: The case is of the rimless type and is lightly necked.

Propellant: Graphited smokeless powder in flat 4mm squares poured loosely into the case and sealed in with a cardboard disk. The weight of the propellant is 75.1g

Color and markings: Black body, red nose tip, yellow body band.

Characters stenciled on body: (Ho 204)


Fuzing: Type 4 super-detonating fuze.

Remarks:
The ammunition for the Ho 204 uses the same projectile as the Ho 203 ammunition but the case is longer. The projectile is constructed in two pieces: a straight sided main body and an ogival-shaped nose which screws into the main body. There is only one cavity into which both the incendiary and high-explosive filling are pressed.



37mm Practice Projectile




Overall length of projectile: 124mm
Length of case: 144mm
Length of complete round: 247mm
Diameter at bourrelet: 37mm
Width of rotating band: 8mm
Filling: Sawdust

Used in: Ho 204 aircraft cannon

Color and Markings: Black overall

Fuzing: None

Remarks:
This projectile has the appearance of an A.P. projectile. It is filled with sawdust and has a cavity closed by a base plug.




37mm Ammunition

While we have already gone over some examples of 37mm ammo, we finally start seeing the types used in anti-tank and anti-air guns. In fact, the 37mm rounds vary depending on which make and model of gun it was supposed to be used in, having some notable differences in case length.





There are eight 37mm anti-tank and tank guns, all sizes of which use the same projectiles but have different cartridge cases.




Propellant:
Type 11th year infantry gun: 1.85oz of graphited smokeless powder in the form of flakes poured into the case and sealed with a cardboard closing disc.
Type 94 tank gun: 2.7oz of graphited smokeless powder ub tge firn if rectangular flakes.
Type 94 AT gun, Type 98 Gun, and Type 100 Tank Gun: 4.3oz of graphited smokeless powder in the form of unitubular grains contained in a silk bag.
Type 97 AT gun: 5oz of graphited smokeless powder in the form of short, cylindrical grains contained in a silk bag.



Type 94 37mm High Explosive Projectile




Type 97 AT (97)
Type 94 AT (94AT)
Type 94 Tank Gun (94T)
Type 1 Anti-tank / Tank Gun (1AT/T)
Type 11th Year Infantry Gun (11th)


Overall length of projectile: 125mm (No fuze) for all types
Length of complete round (Fuzed): (97) 349mm (94AT) 266mm (94T) 223mm (1AT/T) 349mm (11th) 221mm
Diameter at bourrelet: 37mm for all types
Width of rotating band: 8mm for all types
Weight of projectile, filled: 595.1g
Filling: Picric Acid and TNT

Used in: All 37mm guns

Colors and Markings: Black body, red nose band, yellow body band (some rounds may have white body band added)

Fuzing: Type 93 small instantaneous fuze.

Remarks:
This steel projectile is filled with TNT and picric acid. The after two-thirds of the projectile cavity is filled with high grade cast TNT. The forward one-third of the projectile cavity is filled with picric acid. The entire bursting charge is enclosed in a heavy waxed paper casing with a double thickness between the TNT and picric acid charge.


Type 94 37mm Armor-Piercing High Explosive Projectile




Overall length of projectile: 114mm (No fuze) for all types
Length of complete round (Fuzed): (94AT) 262mm (94T) 228mm (97AT) 345mm (11th) 218mm
Diameter at bourrelet: 37mm for all types
Width of rotating band: 9.5mm for all types
Weight of projectile, filled: 1 pound 1/4 oz
Filling: Picric Acid

Used in: Type 11th Year Infantry Gun, Type 94 Tank Gun, Type 94 Anti-tank Gun, Type 97 Anti-tank Gun, Type 98 Tank Gun, Type 100 Tank Gun

Color and Markings: Black body, red nose tip, white body band

Fuzing: Type 94 small delay base fuze

Remarks:
This projectile is made of high grade steel. The main charge cavity contains a small wooden plug in the forward portion and a paper covered picric acid charge aft of the wooden nose plug. The Type 94 small delay base fuze screws into the base of the projectile, also acting as a base plug.


Type 1 37mm High Explosive Projectile




This round is used in the Type 94 Anti-tank gun and the Type 1 Anti-tank gun.

Overall length of projectile: 104mm (no fuze) for all types
Length of complete round, fuzed: (94AT) 250mm (1AT) 333mm
Diameter at bourelet: 37mm for all types
Width of rotating band: 11mm for all types
Weight of projectile: 1 lb 6 oz without explosive
Filling: Picric Acid

Used in: Type 1 Tank Gun, Type 1 Anti-tank Gun, Type 94 Anti-tank Gun

Color and Markings: Black body, red nose tip, white body band.

Remarks:
This projectile is constructed of high grade steel. It has no sharply defined bourrelet. It uses a small Mk 1 base fuze which also acts as a base plug.


Next Time: 40mm and 47mm IJA projectiles

2 comments:

  1. Your site is the only one that says the Ho-203 shell was only 436.2g instead of 475g. Was there more than one shell used by aircraft with this cannon, and what was the weight or % of HE/I fill?

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    Replies
    1. To be honest, it could be an error on the part of the Technical Manual the info is taken from. If you search around, it should be TM 9-1985-5.

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