Materials on the 6.5mm Arisaka gunpowder quantity.

ウォルフガング・ゴッテンベルク【残余二万文字】 @C11katao

Hello, my followers. How are you? Today we're going to talk about a very interesting document. It's also in English. That's because I've never seen this document mentioned by anyone outside of Japan. This may be even more so because it is a minor text even in Japan.

ウォルフガング・ゴッテンベルク【残余二万文字】 @C11katao

I am now talking about the 6.5 mm ammunition used by the Japanese Army. It is also the ammunition stamped with a "G" that is often misrepresented.

ウォルフガング・ゴッテンベルク【残余二万文字】 @C11katao

You can access the text from the URL here, but not many people will be able to read it. After all, even I, a Japanese, had a hard time reading it. jacar.archives.go.jp/das/image/C020…

ウォルフガング・ゴッテンベルク【残余二万文字】 @C11katao

The text states that when making 6.5mm ammunition, the amount of gunpowder is increased or decreased so that the performance does not change.

ウォルフガング・ゴッテンベルク【残余二万文字】 @C11katao

But it also comes with some very interesting test results. The test was to refill the amount of gunpowder to 2.15 grams, 2.05 grams, and 2.23 grams and fire it with an Arisaka rifle. Three Arisaka rifles were used, and the average value of the rifles was carried.

ウォルフガング・ゴッテンベルク【残余二万文字】 @C11katao

This is the table that appeared in it. It's very hard to read, but I'll just pick up where I need to. Even the numbers are in kanji. From the right, at 2.15 grams, at 2.23 grams, at 2.05 grams. pic.twitter.com/jyfdXYa8JJ

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ウォルフガング・ゴッテンベルク【残余二万文字】 @C11katao

2.15 grams is the standard gunpowder quantity for 6.5 mm Arisaka. The maximum initial speed was 767.3 m/s, the minimum was 750.7 m/s and the average was 757.3 m/s.

ウォルフガング・ゴッテンベルク【残余二万文字】 @C11katao

And the pressure inside the barrel was 3630 atmospheres at the maximum, 3320 atmospheres at the minimum, and 3470 atmospheres on average.

ウォルフガング・ゴッテンベルク【残余二万文字】 @C11katao

2.23 grams is a very generous amount of gunpowder. The way I see it, this has probably never been used, at least not in an infantry unit. Highest initial speed was 765.1 m/s, lowest was 754.4 m/s and average was 760.3 m/s

ウォルフガング・ゴッテンベルク【残余二万文字】 @C11katao

The pressure in the barrel of the gun was 3715 atmospheres at the highest, 3495 atmospheres at the lowest, and 3622 atmospheres on average.

ウォルフガング・ゴッテンベルク【残余二万文字】 @C11katao

Lastly, 2.05 grams. It is said that it was often used in the Japanese Army machine guns, and in some cases in sniper rifles. This is also why there was a "G" stamp on it.

ウォルフガング・ゴッテンベルク【残余二万文字】 @C11katao

If you look at the top of the table, you'll see that the gunpowder types are exactly the same, or as close as possible, and not of such a special specification that they contain glycerin.

ウォルフガング・ゴッテンベルク【残余二万文字】 @C11katao

Now, let's see the results. The highest initial speed is 765.7 m/s, the lowest is 752.3 m/s, and the average is 757.3 m/s.

ウォルフガング・ゴッテンベルク【残余二万文字】 @C11katao

Yes, the starting speed isn't much different from the normal one. From a practical point of view, it can be said that they are the same ammunition. But the biggest difference is the pressure in the barrel of the gun, shown below.

ウォルフガング・ゴッテンベルク【残余二万文字】 @C11katao

The maximum was 3425 barometric pressure, the minimum was 3300 barometric pressure and the average was 3377 barometric pressure.

ウォルフガング・ゴッテンベルク【残余二万文字】 @C11katao

When I look at these results, I don't believe that I've heard about the reduction in recoil. Since the bullets in the shell casings are the same, the same amount of recoil should come, according to the law of action-reaction, if generally the same initial speed is given.

ウォルフガング・ゴッテンベルク【残余二万文字】 @C11katao

But at the same time, I don't rule out the possibility that it could have helped reduce the muzzle flash, and I think that's entirely possible. And it would have had the effect of prolonging the life of the gun barrel.

ウォルフガング・ゴッテンベルク【残余二万文字】 @C11katao

The development requirements for the new machine gun (which later became a three-year heavy machine gun in the Japanese Army), which was under development at the time, called for a solution to the short barrel life of the Type 38 machine gun.

ウォルフガング・ゴッテンベルク【残余二万文字】 @C11katao

I believe that "G" ammunition was used to extend the barrel life of machine guns.

ウォルフガング・ゴッテンベルク【残余二万文字】 @C11katao

In practical terms, the sights of 6.5mm Arisaka ammunition with a "G" stamp on it and ordinary 6.5mm Arisaka ammunition without the "G" stamp would not be different and were generally interchangeable.

ウォルフガング・ゴッテンベルク【残余二万文字】 @C11katao

In fact, the manual for the '11 light machine gun even states that it uses the same ammunition as the rifle. It's also a manual for officers. What do you think, my followers?