"Not heard this before about the JS-2 / IS-2...true? false?" Topic

"…a design fault was noticed by the Germans. Because the 122mm gun was so big the Russian gunner had to depress the gun all the way down to enable it to be loaded and then raise the gun back up to find its target again. This meant that the IS-2 tank had a poor rate of fire which proved to be a very critical negative ability in a tank battle. The slow loading IS-2 Russian tanks could not compete with the rapid firing Tiger Tanks."

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Is that correct? I was aware that the JS / IS-III had trouble firing from hull down because the gun couldn't be depressed very far, but this the first I'd heard of the previous model having the opposite problem.

Nice photo of a survivor anyway…

Hi Cuirassier, I am pretty sure that modern Soviet/Russian tanks with an autoloader brought the gun to a level (?) position for the autoloader to do its thing, after which the gun returned to the firing elevation. However this is the first time that I'm hearing this sort of thing for the IS-2. As far as I am aware the poor rate of fire originates primarily from the 2 piece ammunition which is too heavy for the human loader to manhandle as a complete round, and secondarily from the poor/cramped layout in the turret.
I am sure that there are others on this forum who are more knowledgeable than I who shed a brighter light on the subject.

What Haire said.

An IS2 didn't have too much depression to start with.
Very heavy two piece ammo took time to reload.

The requirement to be a loader was that he was able to lift an ox and not need to know how to spell 'ox'.

The set elevation thing started in the 1960s with the T62 where the gun after firing, would return to a specific elevation in order for the case to be ejected out the back of an automatic door in the back of the turret.

There were significant changes to the breech over the course of the war. Maybe this was a "feature: of the earlier tanks?

This reminds me of certain software. You ask creator how to do a common operation, they describe some complicated procedure, you explain that this is to complicated, they say it's possible, and that's good enough!

Why would you want things to be easy, Comrade? Ease is for the decadent bourgeoisie.

There were two different 122mm guns used in two different marks of the js-2. The initial 43 one was slower to load than the 44. The second gun had an improved breach designed for faster loading. If fast is the right word for 2 maybe 3 rounds a minute.

Andy O'Neal is right.

I'm pretty sure the gun would need to be elevated, not depressed to reload. Since it takes 20-25 seconds to load the shell and charge I don't think changing the elevation to reload would not matter too much.

Wolfhag

The average rate of fire of the IS-2 tank: 1.5 – 2 rounds per minute. Rate of fire of German heavy tanks: 6-8 rounds per minute. The problem is really related to the separate loading of the gun and the cramped fighting compartment of the tank.
Although this also gave certain advantages – a low silhouette and overall small size (comparable to the size of a medium tank). Which, of course, reduced the likelihood of hitting the tank.
Against enemy tanks, the IS-2 was ordered to work in pairs, where one vehicle was engaged in the main battle, and the second covered it during reloading.
And you also need to keep in mind that the IS-2 is not a specialized tank hunter, but an assault tank. Its main role is to attack fortified enemy positions. And here the power of a 25-kilogram high-explosive projectile surpassed any tank of that era.

Here is a short film about the shortcomings of the IS-2 based on an army report on the operation of the tank in the army. The film has Russian subtitles, but you can turn on automatic translation. The general meaning of the information can be quite grasped:

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What Cuprum said. The IS2 was a turreted assault gun, not an anti tank, tank. Otherwise it would have been armed with a 100mm AT gun, not a 122.

I'm pretty sure the gun would need to be elevated, not depressed to reload.

Thanks Wolfhag my thoughts exactly.

And you also need to keep in mind that the IS-2 is not a specialized tank hunter, but an assault tank. Its main role is to attack fortified enemy positions. And here the power of a 25-kilogram high-explosive projectile surpassed any tank of that era.

That kind of HE shell is certainly a pretty scary prospect for an infantryman defending a fortified line.

Technically, however, there was one WWII turreted tank that could lob an even heavier shell, the KV-2 tank with its 152 mm howitzer, that was similarly designed for attacking fortified positions, but did not prove a very practical design.

Otherwise it would have been armed with a 100mm AT gun, not a 122.

From what I have read, also the 100 mm gun was initially considered for IS-2, but dropped in favour of the 122 mm. However, the SU-100 assault gun that entered service a bit later was armed with the 100 mm gun, making it potentially scary tank destroyer.

Iirc PSC include an option to build the 100mm gun version.