Japanese 30mm tracer round nerf

Thanks a lot! There is good amount of data about the shells themselves. I also added Ma-202 into the suggestion.

I suppose there isn’t much about 57mm Ho-401 and Ho-402 ammunation?


Can you add the one about this part:

If there’s more information about the muzzle velocity of different shells, for example the 12.7mm Ma-102, I would also appreciate it :)

I already found the Ma-103, which apperantly was 803.5m/s.


I read the book carefully, but could not find out the amount of explosives filled in each shell, and the muzzle velocity of each shell.

This is the source page for the description of Ma bullet.

Ma-102 (special incendiary round)

  • This ammunition detonates when it strikes duralumin of 0.8 mm or more in thickness, exerting destructive and incendiary effects. There is no fuse. It is prohibited to use at temperatures above 150°C because it will self-destruct at temperatures above 200°C. Incendiary effect is superior to that of white phosphorus incendiary rounds.


  • This is an HE round with a Type 93 small instantaneous fuse in the nose. It is filled with explosive and incendiary composition. Safe against normal impact. Safe against barrel heating.

Handling Precautions for Ammunition:

  • Tracer rounds lose effectiveness when exposed to humidity, so handle them with care.
  • While incendiary rounds, Ma-102, and Ma-103 do not spontaneously ignite, it’s advisable to store them in cooler conditions, especially in tropical regions.
  • Avoid subjecting Ma-102 and Ma-103 to excessive impact.
  • When using these HE rounds, pay attention to propeller synchronization. Impacting the propeller with this ammunition can create a hole with a diameter of 3 cm.


  • Same functions as Ma-102.


  • When this shell hits a duralumin plate 3 mm or thicker, it detonates and produces an incendiary effect. The fuse does not function on duralumin plates less than 2 mm thick, and the shell simply penetrates.

Source: Jiro Sayama. Japanese Army Air Weapons. 2021. ISBN-13: 978-4769831976. pp. 290-291, 510-511

The Japanese studied the captured B-17s and looked for weaknesses. The self-sealing tanks on US B-17, B-24, and B-29 aircraft were installed behind 1-2mm thick duralumin plates. The outer layer consisted of 3 mm thick horsehide, followed by an intermediate layer of 10-20 mm thick natural rubber and sponge, and finally an inner layer made of gasoline-resistant synthetic rubber. Special ammunition was required to ignite gasoline leaking from these fuel tanks.

The Japanese Navy has also developed incendiary shell model 2, similar to the Army Ma rounds.
The 20 mm HE-I shell model 1 on the left has an air column fuse and is designed to allow the blast to exit in the nose direction, resulting in larger fragments and a large hole in the self-sealing tank. The amount of explosives filled is daringly low because the incendiary composition burns in an instant when more explosives are used, reducing the incendiary effect. The 20 mm HE-I shell model 2 on the right has an impact fuse, and development began in October 1943 to improve safety and power from model 1. In February 1944, field tests were conducted and the HE-I shell model 2 was confirmed to be very powerful, and it was adopted as the official weapon.


Jun Okamura, “20 mm HE-I shell for B-29 self-sealing tank.” The Complete Story of Aviation Technology, Vol. 2, 1955, pp. 159-160, Appendix: List of Aviation Ammunition Specifications


Interesting to know. Seems like that flashpowder is just the better incendiary component compared to phosphorus.

Ah so that’s the downside of the fuzeless round. If the barrel heats up to much, they’ll end up wrecking your gun 😂


That seems like an amazing book. Too bad even otherwise very good Western books don’t have such detail about Japanese rounds. Overall 1950s and 60s Japanese sources remain unknown to us.

Do you have anything about Ho-402 ammo? Today my suggestion about Ki-93 passed, though the ammo data was still lacking.


But there was allready enove info for it to be usable in game, the Ho-402

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That’s true, but there is still little room for improvement.

I saw that earlier, congrats on that! Though I don’t expect much out of that plane.


Finding sources for information on Ho-402 ammunition has been difficult for me.

The projectile weight of the Ho-402 is 2,700 g. Since the projectile weight of the Type 1 AP shell of the 57 mm tank gun and the anti-tank gun is 2,700 g, this AP shell probably could have been fired by the Ho-402. Since the 57 mm anti-tank gun has a HE called long HE shell with a longer projectile and more filled explosives, this HE shell could also have been fired by the Ho-402. However, extremely long projectiles will not fit due to the limited length of the magazine for the Ho-402.

57 mm Type 1 APHE-T shell

57 mm long HE shell (high capacity HE shell)

57 mm Ho-402 cannon mounted on Ki-93


  • Japanese Army artillery, Infantry gun, Anti-tank gun Written by Jiro Sayama. July 2011. ISBN-13:‎ 978-4769826972. pp. 205, 309
  • Illustrated Warplane History: Imperial Japanese Army Warplane (日本陸軍軍用機集) . Written by Shigeru Nohara. June 1997. ISBN-13: 978-4766332094. pp. 1, 205
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