According to the engineer who developed the gun sight for the Type 61 tank, the US-made tanks owned by the JGSDF were equipped with either the M71 telescope with 5x magnification or the M83 telescope with variable magnification of 4x-8x. There were also considerations to equip the Type 61 with an improved version of the M83 telescope.
J1-M83 Direct Telescopic Sight
Manufacturer: Topcon, 90 mm tank gun sight for medium tanks
Magnification: 4x to 8x
Field of view: 13° to 6°30′
The JSDF uses tanks supplied by the US. These US-made tanks are equipped with M71, M83, and M85 telescopes. The tank spare parts are manufactured domestically in Japan, and the gun sights are produced and repaired by Japanese optical equipment manufacturers. The supply and repair of the M71 and M83 telescopes are handled by Ofuna Optical Instrument Manufacturing Co., Ltd. A modified version of the M83 telescope, the prototype J1-M83 telescope, was developed. However, since other prototype sighting telescopes offer even higher performance, the adoption of this sighting telescope is expected to be discontinued.
— Yasufumi Emori, former member of the Optical Section, 1st Research Institute, Technical Research and Development Institute, Ministry of Defense. “The Optical Weapons and Their Usage (Part 1)”
If both sights were used, then I suppose it can at least be send as a suggestion. I don’t think they’d want to add such thing as modification only for this one tank.
Now I’m interested to learn more about Japanese tank gun sight history. I find it curious how ST-A1 and 2 have 8-16x sights (at least in WT), but Type 61 goes back to 4-8x sights. Is there something about that in the same book?
I was reading through the japanese wikipedia page on the Type 61 and I found something interesting.
Says here that an APFSDS shell was prototyped and tested for the Type 61. There’s no source given for this statement in particular, so maybe it is tucked away in one of the sources? I imagine 90mm APFSDS wouldn’t be terribly useful but it’d be kinda cool.
Edit: the “M332A1 HVAP-T” is an APCR shell, likely the one found on the M47. I didn’t recognize the name at first. Not the dart in question obv.
Apparently Chi-To Late’s ammo racks are going to be fixed in the coming big update and there are hopes for some others as well. So far we have managed to report Chi-Ri, Chi-To Late, Chi-Nu and Chi-He. Strangely enough Chi-Has have proven the most difficult.
Perhaps some document or book somewhere contains a proper drawing, but so far we haven’t found anything like that. Instead I’ve been scraping together photos and some parts from video. Any help would be welcome. Below is what I found about Chi-Ha Kai. The original 57 Chi-Ha is even more difficult.
In the hull the central rack by the gearbox is correct. Also the 8 round rack by the wall is kind of correct, but it should be by the right side, instead of left.
Large portion of the ammo is actually stored at the left back corner. I found two photos of it from two separate tanks, but neither of them show it fully. It should contain about 30 rounds.
So far that’s about 87 out of 100 rounds, depending on how many exactly there are in the rear rack.
Rest of the main gun ammo was probably stored in the two boxes on the floor. Then again they could as well be for machine gun ammo. In either case it’s too difficult to estimate their capacity.
According to Type 90 (B) specification, the lowest magnification of gunner’s sight is 1x.
That of type 90 was not archived. Type 90 Type 90 (B)
Spoiler
According to this table, the commander’s sighting periscope has 3x zoom low mag system and 10x zoom high mag system.
The gunner’s sighting periscope has a 1x zoom observation system and a 10x aiming system.
I couldn’t find whether the low/high mag system and the observation/aiming system can be switched continuously or not.
There is also a 12x zoom aiming telescope that can be used by the gunner.
The thermal imager may have a software zoom function, although the magnification itself is not shown. There are 3 FoV modes: wide view of 7.6°x10.1°, narrow view of 2.7°x3.6° and magnified narrow view of 1.3°x1.8°. The magnified narrow FoV mode has approx half the FoV of the narrow view mode, so it has twice the magnification. Assuming that the narrow FoV mode has a 10x zoom like other high-mag modes, the magnified narrow FoV mode has a 20x zoom.
Chi-He, Chi-Nu, Chi-Nu II and Chi-Ri racks were updated as well. Also Ho-Ro gun angles and location of radio in several vehicles. Community Bug Reporting System
According to US reports, the Type 97 Chi-Ha carried 121 rounds of 57 mm ammo, however, Japanese sources state that it carried 114 rounds. The Chi-Ha’s hull held four 57 mm ammo boxes divided into 40, 36, 21, and 7 rounds, while a 10-round rack was installed in the turret.
“The shells are stored in aluminum alloy ammunition boxes. Due to space constraints inside the vehicle, they are divided into four boxes containing 40, 36, 21, and 7 rounds respectively. Additionally, a 10-round ammunition box is mounted on the turret side plate, bringing the total to 114 rounds.”
「砲弾はアルミニューム合金製の弾薬箱に収容され、車内余積に格納される関係上、40発、36発、21発、7発の4箱に分割される。加えて砲塔側板には10発の弾薬箱が取り付けられており、合計114発である。」
