Army 40mm caseless gun Ho 301

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#1

These gun was inspired by the army mortar Type 89. The 50mm shell has two compartments, a front compartment holding the explosive charge and a back compartment with the propellant. These mortar was a rifled muzzle loader and the shell used a plain copper driving band. It was fired by a striker pin hitting a central primer cap - the propellant blow out the driving bands into the rifling and shoot out the shell.

Cutaway by D.Harms

Very similar to that is the 40mm ammo. The gun is a blowback system using a 10 rd. box magazine and fire the 40 x 129 shells (caseless) with a conventional copper driving band. The gun fires 425 rds./ min with a velocity of 245 m/ sec. With a weight of 40 Kg and a length of 1, 39 meter it was a compact gun.
The shell used a somewhat different alluminium fuze better suited to aircraft use, a 40mm caliber and a somewhat bigger propellant compartment.

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#2

Interesting; I think I saw some test in Aberdeen of this rare weapon in an old book, let me see if I can found it.

#3

Yes would be nice if you could add it. The one gun on the site you posted from the Chinn book showes one Ho 301 in the experimental class.
The base plate in the above foto, was made for US trials.

#4

Jawhol, here is:

Enjoy

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#5

Sorry about the messy layout of the pictures but is the forum fault not mine.

#6

Very nice Panzerknacker. Very nice pics of the dismantled gun.

#7

No problem, is my pleasure, pics fixed by the way.

I believe the only aircraft wich used this cannon was the Ki-44.

#8

Yes in great numbers only in the Ki 44 Tojo. They where planned for some experimental army fighters.

Ho 301 in wing mount Ki 44 Tojo

Close up of an Ho 301 captured at Clark field.

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#9

Very good. :slight_smile:

Do you know wich was the magazine capacity ?, the late source say 10 rounds, but it sound too little for practical use.

#10

The Tojo with 40mm guns where used to fight the B 29. How many runs they made. and how many time there wass to fire - 3 to 4 runs - 3 seconds to fire -
may be 10 round are enouth. Its a spring loaded magazine - may be not that easy to make it longer. All sources I know say 10 rd box magazines - yes.
It is interesting that the Ho 203 was used in Ki 44 wing mounts too.

#11

Well, yea, after all it was a 40 mm weapon, 2 or 3 hits should be enough.

#12

Most definitely !!! :mrgreen: