Anti-armor weapons of the japanese infantry.

[tom!]

Hi.

Type 1 47 mm at-gun:



In 1938 the japanese Kwantung Army captured some soviet 45 mm at-guns. The Army Technical Bureau started some intense testing. The gun was found superiour to all own models and as it was based on the already introduced type Ra 37 mm gun (it was in fact an upgunned version of the 3,7 cm Pak Rheinmetall) the decision was made to start the development of a similar weapon with a caliber of 47 mm.

There were two large handicaps slowing down the development:

1. The Army High Command saw no use for such a gun
Therefore the development was seen as "basic research" and not supported properly
2. The main requirement for all infantry support weapons was a weight limit to allow easy transport of the weapon by the crew.
Even the type Ra at-gun reached the limit and so an equilibrium had to be found between weight and effectiveness lowering the ap-abilities of the first test guns noticeably.

With the devastating results of the Nomonhan-Incident in 1939 showing a lack of Antitank defense ability of the infantry the weight limit was dropped and the development of the 47 mm at-gun was fastened . In September 1939 the production and testing of the final construction started.

The gun was in general an enlarged version of the type 94 rapid-fire infantry gun using the same breech type and firing mechanism. Two tires allowed a maximum transport speed of 50 kph. The shield was mounted angled. With a total weight of 750 kg the gun was too heavy for crew transport and the penetration of 50 mm/90° on 500 m was compareable to at-guns of other countries of that time.



Production started in Spring 1941 at the Osaka Army Arsenal which tested all guns and supervised allmost all artillery and at-gun production for the japanese Army.

The guns were used in the regimental at-companies.



During 1942 the few guns produced were found useful against the lightly armoured allied vehicles and light tanks but useless against the Mathilda II. After the US Medium M4 reached the battlefields the guns became almost totally useless.

Additional ammunition research lead to an increased penetration of 45 mm/90° on 700 m but the frontral armour of the Sherman still could only be penetrated below 50 m and the side armour below 250 m.

Some 2300 guns were produced and used until the end.

The gun was also mounted on an enlarged gun mount of the type 98 37 mm tank gun and introduced as type 1 47 mm tank gun. This gun was used with the type 97 medium tank Shinhoto Chi-Ha, type 98 experimental medium tank Chi-Ho, type 1 medium tank Chi-He, type 3 amphibious tank Ka-Chi, and type 5 experimental amphibious tank Ka-To in bow-mount.



Yours

tom!

[Panzerknacker]

This 47 mm weapon was the most close that the japanese have to a decent Antitank weapon, still weak.

Very good Information as usual Tom.

Type 2 AT Rifle Grenade

In 1942, a new AT grenade was bought by a disguised merchant vessel to Japan from Germany. It was a hollow charge grenade and a gift to Hirohito from Hitler.
In AT grenade, there were two kinds of caliber, 40 mm and 30mm. The inner barrel of the grenade launcher was rifled and that rifling was reproduced in the rear of the grenades to give the spin stabilization.

Though it was officially anounced that it can destoy a 40 mm thick armor, actually it was almost useless againt Allied medium tanks.

[tom!]

Hi.

40 mm hollow-charge rifle grenade:



impact fuze

from top:
- booster
- detonator
- creep spring
- clock spring
- striker
- arming sleeve
- striker carrier
- arming spring

data:
over-all length: 202,7 mm
maximum diameter: 40,2 mm
total weight: 353 g
filling: 50/50 RDX/TNT
weight of filling: 108 g

description:
This grenade is a copy of the german "große Gewehrpanzergranate" and is fired from a cup launcher attached to the standard 6,5 mm rifle.
The body is cylindrical with a semiconical shaped head. It is made in two parts threaded together and fitted with a ballistic cap and cone to give the kollow-charge effect. The forward part contains the explosive charge cast around the cone. The after part which is made of aluminium had a rifled collar near the base and contains the fuze ans explosive train.
The fuze is held in by a base plate with a protruding spigot which is screwed into the base of the grenade. The fuze is held in position by the spigot. The needle firing pin is secured in a housing that has four stirrup-like springs protruding from the side. Around the housing is a setback spring held in by an arming sleeve which has two sets of grooves notched on the inner side. Holding the firing pin stationary is a coil clock spring which is held in by the arming sleeve. There is also a creep spring between the firing pin and the detonator.
The propellimg charge consists of a special cartridge with a wooden bullet.

operation:
On firing, the setback causes the arming sleeve to move down and it is held down by the stirrup springs which engage in the groove in the arming sleeve. Centrifugal force then causes the clock spring to expand and the fuze is armed. On impact the firing pin housing overcomes the creep spring and moves onto the flash cap setting off the detonator and booster

The 40 mm rifle grenade was also used in CBUs as type 2 1/2 kg hollow-charge bomblett with a diferent fuze and an attached fin.


30 mm hollow-charge rifle grenade:



data:
overall length: 158,6 mm
maximum diameter: 29,97 mm
total weight: 233,89 g
filling: 50/50 RDX/TNT
weight of filling: 49,6 g

description:
The explosive head of the 30 mm grenade is of the same type construction as that of the 40 mm grenade, but on a smaller scale. The spigots of both grenade types are identical with the exeption of the threads on their forward ends. Both grenades use the same fuze

operation:
The operation of the 30 mm grenade is identical to that of the 40 nn grenade.


Both rifle grenades were fired by the type 2 cup-type rifle grenade launcher, see next post (due to limitation of pictures per post).




By the way, the pic panzerknacker posted in his last post shows two versions of an experimental 45 mm hollow-charge rifle grenade and on the right the final version of this grenade for the type 2 launcher


Yours

tom!

[tom!]

Hi.

Type 2 rifle grenade launcher:



The type 2 grenade launcher is a copy of the german "Schiessbecher". Examples of the German Schiessbecher and its antitank (hollow-charge) grenades were delivered to Japan by blockade breaker. Two blockade breakers with identical cargos were sent to Japan to improve the odds of the mission’s success. The blockade breaker Tannenfels arrived in Japan first, on 12 May 1942. By August of 1942, the Type 2 and its hollow-charge grenades were being produced, and some examples had reached Guadalcanal by October of 1942. Production of the Type 2 grenade launcher was halted in 1943. Approximately 49,000 Type 2 grenade launchers were produced from 1942 to 1943. This figure is very small when compared to the more than 1.4 million Schiessbecher that were delivered to German troops from 1942 to 1944.



All known examples of the Type 2 grenade launcher were made by the Chigusa factory of the Nagoya Army Arsenal. The Type 2 was used with the Type 38 6,5 mm or Type 99 7,7 mm rifle.
The physical characteristics of this launcher remained stable throughout its short production period; however, variations in the launcher’s markings have been identified. Early launchers were dated using the Showa era, and later launchers were dated using a secret code.




Two hollow-charge grenades were used with the Type 2 grenade launcher--a 30 mm version and a 40 mm version. Two types of launching cartridges were used; one had a wooden bullet, and the other had a crimped case mouth. The Type 2 grenade launcher was issued with a canvas carrying pouch, barrel wrench, and canvas pouch for carrying 10 rifle grenades.



Yours

tom!

[tom!]

Hi.

experimental 57 mm at-gun:



Realising that the type 1 47 mm at-gun will not be capable of destroying the newer allied tank designs the japanese Army started the development of a 57 mm version in April 1941. The gun should also be used as main armament of the succesor of the type 1 medium tank Chi-He.

The type 1 at gun was enlarged to cope with the higher recoil forces of the 57 mm gun. This increased the weight to 1600 kg which was indicutably high. All tries to lower the weight meant to lower the penetration ability. The last design could only penetrate 60 mm/90° on 1000m at a weight of 1540 kg.

The japanese Army had to realize that a good at-gun-design would be too heavy to be used with the actual infantry doctrine. The development was stopped in 1943 and the capacities were used to design a mobile, self-propelled at-weapon.


experimental 37 mm at-gun Raku:



In early 1942 the japanese Army started this project based on the type 1 37 mm at-gun for the planned airbourne regiments. The main task was to develop a lighter and smaller gun with the same penetration ability as the type 1 at-gun. The gun should be disassembleable to be packed into two containers which should be dropped from transport aircraft.



The wheels were redesigned with stabilising metal circles. Using a small box carriage and a smaller shield the total weight could be lowered to 243 kg. The efficiency was compareable to the type 1 at-gun but this weapon was found too weak to get used in further battles.



The design was cancelled in 1943.

Yours

tom!

[Panzerknacker]

Very good, I have no idea of the experimental 57 mm gun, look rather similar to the british 6 pounder.

[Nickdfresh]

Very good info Tom...

[tom!]

Hi.

Type 4 70 mm rocket launcher:



In early 1943 the japanese Army was able to capture some US 60 mm Bazookas. As these weapons were extremely light and had a larger penetration ability than most japanese at-guns the decision was made to develop a similar weapon.

In late 1943 design data of the german Raketenpanzerbüchse 54 were delivered to Japan speeding up the own development. In early 1944 the 70 mm rocket launcher (exact caliber 72 mm) was tested at the Osaka Army Arsenal.

To minimize the transport size the launcher could be disassembled into two parts. The firing mechanism was copied from the US Bazooka. A bipod could be attached to the 1500 mm long barrel. Total weight was 8 kg.



The rocket propelled grenade had a total length of 359 mm and was projectile-shaped with small fins giving a rotation to stabilize the flight. Muzzle velocity was 160 m/s with a propellant weight of 260 g and a burntime of 0,4 sec.

Minimum range was 50 m to arm the fuze which was armed after few rotations. The maximum range was 800 m, maximum effective range 100m with a hit accuracy of 60%. The penetration ability of the hollow-charge warheads with an explosive weight of 700g was 80 mm. The inmpact fuze only worked in hit angles between 90° and 60°. Below 60° the warhead didn´t detonate.



The two-men-crew consists of gunner and loader. An experienced crew could reach a rof of 6 rpm. A total of 3300 type 4 rocket launchers were produced at Ogura and Osaka Army Arsenals from July, 1944. All were given to units preparing for the homeland defence, non were used outside Japan.


experimental 90 mm rocket launcher:



As the penetration ability of 80 mm was found too weak in early 1944 an enlarged version was ordered. In late 1944 a test version with a barrel length of 1500 mm was produced and tested. A third leg was attached behind the trigger element to increase stability during firing. With a total weight of 12 kg a 8,6 kg rocket propelled grenade could be fired. With a propellant weight of 620 g, giving a muzzle velocity of 106 m/s, the warhead, filled with 1,6 kg explosive, was able to penetrate 120 mm on 100 m. A short version with a 1200 mm long barrel was developed for the airbourne units. There is no report of a serial production.

Yours

tom!

[tom!]

Hi.

type 5 (experimental) 45 mm recoilless rifle:



In late 1944 the decision was made to develop a short-range infantry anti-tank weapon based on the german Panzerfaust but reloadable. This weapon should be light with a hollow-charge warhead giving a minimum penetration of 120 mm.

In 1945 three test versions with different position of the firing mechanism and different barrel diameter were built. All had a conical extension with a length of 380 mm at the rear end to minimize the recoil. All used an experimental grenade with a length of 800 mm, 2,3 kg weight, propellant charge of 35 g and an explosive weight of 500g.



Version 1 had a barrel length of 600 mm and. With a barrel diameter of 45 mm the maximum penetration was 100 mm.

Version 2 had a barrel length of 1000 mm. With a diameter of 57 mm the maximum penetration was 110 mm.

Version 3 had a barrel length of 1000 mm. With a diameter of 45 mm the maximum penetration was 110 mm.

The decision was made to continue development of version 3. The final version had a weight of 6,4 kg, a barrel lenght of 1000 mm and the 380 mm long conical rear extension.



Different types of rocket propelled grenades were tested with propellant charges of between 30 g and 100 g. The explosive weight was increased to 625 g, the total weight was still 2,3 kg.

The final version had total lenght of 850 mm with a propellant part of 180 mm length, a propellant weight of 100 g, a 520 mm guidance stick with an impact fuze on top and a warheas of 150 mm with an explosive weight of 625 g. Muzzle velocity was 40 m/sec., minimum range 50 m, maximum range 150 m, penetration 120 mm.



Yours

tom!

[Panzerknacker]

Beatiful.

Checking the last picture of the hollow charge grenade I think the japs should give more lenght between the end of the copper cone and the grenade head, the hollow charge need more espace between the charge and the armor to made the best use of the fire jet.

[tom!]

Hi.

experimental tank hunter studies:

As effective at-guns would be too heavy to be used with the standard infantry doctrine some designs were started to increase mobility of larger caliber guns.

light anti-tank gun carrier So-To:



1939 gun carrier study bassed on the type 95 light tank Ha-Go. The gun could be attached on top of the closed fighting compartment. The carrier was planned for the type 94 37 mm infantry gun/type 1 37 mm at-gun and the type 1 47 mm at-gun


47 mm tank hunter study:



A tank hunter based on the type 94 tk special tractor with gun firing to the back. The fighting compartment is open to the top and back.


type 5 experimental 47 mm tank hunter Ho-Ru



Experimental tank design based on the type 3 light tank Ke-Ri with closed fighting compartment similar to the german Sturmgeschütze. The design was abandonned just before the prototype production should be started as the 47 mm at-gun was found too weak and the type 5 75 mm tank hunter Na-To became ready for serial production.

Yours

tom!

[tom!]

Hi.

Type 5 tank hunter Na-To:



In 1943 the decision was made to develop a tank gun based on the type 4 75 mm aa-gun which became operational in early 1944.

For this gun a special gun carrier should also be developed, based on the chassis of a newly designed full-tracked heavy transport vehicle using a remodelled chassis of the type 4 experimental tank Chi-To.

A prototype was built in April, 1944. The engine of this vehicle was placed in the bow. The engine room and the driver cabin for the driver and the wireless operator were armoured with welded 12 mm thick armour plates.
Behind the driver´s cabin the type 4 75 mm tank gun should be placed on a special pivot mount. A 12 mm gun shield should covered the 5-men gun crew from infantry ap-rounds, but only from the front. The chassis was tested in summer 1944 showing a large vulnerability of the gun crew regarding infantry fire from the sides. This was solved by installing two aditional side armour plates on both sides of the gun mount.



The gun prototype was also tested in Summer 1944 showing multiple problems with stability and recoil mechanism making a major redesign necessary. This redesign was done in early 1945. Now there were additional problems with the gun mounts of the type 4 tanks but as the guns on the Na-To were mounted on a pivot there was no problem for the use on the tank hunter.



The completed vehicles were tested in spring 1945 showing a good mobility and cross-county ability. The gun was able to penetrate the US medium M4 on ranges over 1000 m making the vehicle a dangerous weapon. In May, 1945, a couple of type 5 75 mm tank hunter Na-To were sent to northern China for battlefield tests. It is possible that these vehicles were destroyed during the soviet attack in August, 1945 but all documents egarding these late-war developments were destroyed after the japanese surrender.



data:

manufacturer: Osaka Rikugun Zoheisho (Osaka Army Arsenal)
number of vehicles built: total number unknown, but > 10
total weight: 15 t
crew: 7 men
maximum armour strength: 12 mm
length: 5800 mm
width: 2400 mm
height: 2750 mm
engine: Mitsubishi 8 cylinder gasoline engine
power: 165 hp bei 2000 rpm
maximum speed: 40 km/h
power-weight-ratio: 11 hp/t
armament: 1 X Typ 5 75 mm gun

Yours

tom!

[tom!]

Hi.

Now the real heavy things:

Part 1:

From early 1943 a heavy 105 mm tank gun was developed based on an experimental 105 mm heavy artillery gun, a remodelled type 92 105 mm gun. The development was made quickly and with only few problems to solve the design was tested in spring 1944. The tests were done successfully and so in summer 1944 a 105 mm tank gun was ready for service but there was no idea how to use this gun. Due to the weight of more than 5 t and a total length of more than 7 m no actual tank or tank design was able to carry this gun.



data:
caliber: 104,9 mm
barrel length: 4720 mm
muzzle velocity: 900 m/sec
grooves: 32
spin direction: right
ammunition:
projectile: 16 kg
propellant charge: 30 kg
penetration: 150 mm/90° on 1000 m


gun immediately after firing


This lead to a redesign of the turret planned for the super-heavy tank project named O-I. Additionally studies were started to develop a turret for the planned type 5 tank Chi-Ri. Due to a massive lack of resources none of these projects could be finished until mid 1945 and so an interim solution was designed, the

experimental 105 mm tank hunter Ka-To:



This vehicle was based on the design of the type 5 experimental tank Chi-Ri. The planned total weight was about 30 t. The superstructure was similar to the one from the Na-to but had a maximum armour strength of 25 mm. The wireless operator was removed making a smaler driver´s cabin possible. This should give the Ka-To a maximum traverse of + - 45°. The gun was mounted on a pivot lafette and equipped with an armoured housing, only open to the back. Frontal armour was 25 mm, side armour 20 mm, top armour 12 mm.



At the end of the war the design was almost ready for the prototype stage. Most detail documents were destroyed.

planned data:

total weight: 30 t
crew: 6 men
maximum armour strength: 25 mm
length: 7390 mm
width: 2850 mm
height: 2850 mm
engine: Mitsubishi Diesel engine
power: 400 hp
maximum speed: 40 km/h
armament: 1 X Typ 5 105 mm tank gun

Yours

tom!

[tom!]

Hi.

Part 2:

Heavy tank destroyer Ho-Ri:

The japanese Army payed a lot attention on the german heavy Panzerjäger like Ferdinand/Elefant, Jagdpanther and also Jagdtiger. Having a gun with a penetration ability like the german 8,8 cm Pak 43/3 and a chassis for tank weights of up to 45 t the decission was made to build a similar tank destroyer. The design started after the chassis of the type 5 experimental tank Chi-Ri became ready for service in early 1945. In the first stage two different designs were made:

Ho-Ri I:



Using chassis and superstructure of the type 5 tank the engine should be placed in the middle of the vehicle. The gun should be placed in a heavily armoured casemate in the back of the vehicle. The planned armour thickness of the casemate was 150 mm frontal and 100 mm on the sides and back.
For close defence the standard bow armament of the type 5 tank should be used, a type 1 37 mm tank gun with a coaxial type 97 7,7 mm tank machine gun. Additionally machine gun mounts in the sides and the back of the casemate were planned.





Ho-Ri II



Also using chassis and superstructure of the type 5 tank the tank gun should be placed in a casemate installed instead of the tank turret. Armour strenth of the casemate should be the ame as on the Ho-Ri I. For close defence a machine gun should be mounted in the bow and a type 98 2 0 mm aa-machine gun should be mounted next to the commanders cupola. Some changes were made just before the designs should be presented to the Army High Command. The casemate had been simplified for faster building and the type 1 37 mm tank gun was added to the bow machine gun again. On the other hand the aa-machine gun was removed and additional machine gun mounts were added.





The Army decided to develop the Ho-Ri I design and a type 4 20 mm aa-gun twin mount was added to the casemate top. Until surrender only early development stages were finished. Prototype manufacturing was planned for December, 1945.


planned data:

total weight: 40 t
crew: 6 men
maximum armour strength: 150 mm
length: 7400 mm
width: 3050 mm
height: 2700 mm
engine: licence built BMW 12-cylinder gasoline aircraft engine
power: 550 hp
maximum speed: 40 km/h
armament:
1 X Typ 5 105 mm tank gun (60 rounds)
1 X type 1 37 mm tank gun (100 rounds)
1 X type 4 20 mm twin aa-machine-gun (480 rounds)
2 X type 97 7,7 mm machine gun (4980 rounds)

Yours

tom!

[tom!]

Hi.

Type 93 multi-purpose mine:



From top left:

- safety washer
- brass cap
- washer
- safety cap
- brass dome
- shear wire
- spring
- main filling
- striker
- percussion cap
- detonator
- booster

Data:
diameter: 171,5 mm
over-all height: 44,5 mm
weight: 1360 g
explosive weight: 900 g
type of explosive: Picric Acid

Description:
The mine is circular with a slightly domed top and flat bottom. It is constructed of an upper and lower section of sheet metal secured together by four heavy corrugatuions in the walls which serve as threads. The overlap of the walls of the two sections is sealed with a bituninous paint. The interiour of the container is painted with a black enamel to secure the metal from the corrosive effects of the Picric Acid. The explosive is inserted as solid ring main charge of cast Picric Acid with an inner booster of pressed powdered Picric Acid containing a 16 mm diameter central hole to house the fuze. The explosive is completely covered by a layer of paper, shellacked to the explosive and waxed externally.
Soldered on the inside of the lower mine section is a brass disc, 39,7 mm in diameter, having a threaded collar for the insertion of the fuze.
The central hole in the upper section is reinforces with a brass collar threaded to receive the brass plug. A thin leather washer fits between the brass plug and the collar to seal the mine.
Two brass rings are fastened to two opposite sides of the upper section by means of a soldered metal strip. Drag ropes may be fastened to the rings.
The fuze assemby consists of a striker held under spring pressure by a shear wire, a percussion cap, a primary detonator, and a larger secondary detonator all incorporated in the fuze body which is threaded on the lower end to srew into the collar in the bottom of the mine. A safety cap is screwed into the upper end of the striker until the mine is laid. An additional safety feature is a brass cylinder with attached washer which fits over the brass safety cap and rests on top of the fuze body, the washer fitting under the leather washer of the brass plug.
The mine is painted olive-drab with a narrow red ring around the brass plug.

Employment:
Antipersonnel and antitank
The Japanese have two sizes of shear wire for this mine. One for antipersonnel use shears at 32 kg, the other, for antitank use shears at 1135 kg. These mines have been found burried upside down with additional explosives placed beneath them to increase their effect. The A/P fuze has a black upper body

Operation:
With the safety devices removed any load on the cover of the mine causes the brass plug to press down the striker. If the prssure is sufficient, the shear pin is sheared. This frees the striker which, under pressure of the spring, strikes the percussion cap initiating the detonating system.



provisional Panzerfaust:



In 1944 investigations were made by the Army Headquater if a serial production of the german Panzerfaust 100 is possible. Due to the lack of raw materials and industrial ressources a production seemed impossible.

In early1945 guidelines for the defence departments of all prefectures were published how to built weapons for militia units using natural materials. Under these guidelines was one concerning the development and production of Panzerfaust-type at-weapons.

for the barrel bamboo should be used. The inner walls should be drilled out, in order to receive a continuous pipe of about 950 mm. A basket made of bamboo fibers installed at the front end should increase accuracy.

The grenade should be made of a bamboo shaft with a diameter, which had to fit into the bamboo launcher tube, and an up to 300 mm long hollow-charge warhead made of wood or sheet metal usind a steel or copper cone. The propellant charge should have a weight of between 30 and 40 g, the weight of the explosive filling should not exceed 1 kg.



A penetration of 100 mm should be reached in trials. The weapons should be manufactured by local factories and craftsmen.

I do´t know if there was any serial production.

Yours

tom!