Overhaul of Gaijin calculator

If anyone wants to know what certain rounds would look like, PM me the information and I will make a chart.

That is definitely true of wartime ammunition, American analysis of 45mm,57mm and 85mm APHE captured in Korea (Report ADA443218 which is publicly available online), they also consider the shapes used obsolete.

It’s interesting how the Soviets adopted capped AP by using German rounds as references, while the US dropped capped AP.

Is it possible that it was because the Americans realized that it was better to have more penetration at 60° in exchange for losing penetration at 0° while the Soviets continued to prefer penetration at 0°?
The bad thing is that it is not reflected in the game, since the APCBC drill at 60° the same or more than the APBC.

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That’s likely the case. It’s just something I found interesting.

That makes sense.

It must also be taken into account that the APCBC BR-412D ammunition is from 1953, so one could say that it was put into service quite late since the HEAT-FS of the 100mm cannon is from 1955.
Of all, I would not be surprised if they kept the BR-412A ammunition for the tanks destined for export, for example in the Yom Kippur War the arab T-54 and T-55 used the BR-412D ammunition, instead of the HEAT-FS or APDS, which were already available for the Soviet army.
That’s why I find it funny, the T-54 should have the BR-412A as the best ammunition, the T-54A could carry the BR-412D and the HEAT-FS, and the T-55 would carry the previous ones plus the APDS.El Tiran 4, being captured from the Arabs and maintaining the 100mm cannon, it would carry the BR-412D, I imagine that is why the cannon was replaced by the Western 105mm, apart of course from the fact of not having spare cannons and ammunition manufacturing.

How does Gaijin extract angled performance from this calculator? I would be interested in seeing the M103’s, T34’s, T32’s and T54E1’s angled performance with the modified calculator

Gaijin uses standard slope modifiers from WWII Ballistics, Armor and Gunnery.

M103 M358 APBC


T54 T182 APBC


T32 T43 APBC




Wanna see something funny?


The german 7.5cm PzGr.39 is rated to penetrate 100mm/0° at 650m/s. K DeMarre = 2103.
A 6,5kg 76mm shell (BR-350B) with the same K will pen 94mm/0° at 643m/s(100m). In game it pens 98mm/0°

Soviet magic ammo is better not only against sloped armour, but against thick flat plates as well. It’s better in every way, lmao.

I’m still convinced Gaijin based their calculator on Soviet rounds.


APCR carrier weight has a major impact on penetration. This boosts the performance of rounds with small cores in heavy carriers, like the Soviets. The uncapped AP penalty to represent Soviet APHEBC, but they also a get the OP slope modifiers to keep their performance.


I keep forgetting to post this but it was brought Jo again, so here it is. This document compares early AP and APC at 0 degrees and 30 degrees. AP across the board outperformed APC, until the better ballistics of the APC took over.

Note that it says “extrapolation of the results of trials”. Its not accurate, because we know fairly well that, for example, a 5in/30° target is immune (Army limit) from 90mm AP shells at velocities under about 2800fps, unlike this chart implies.





Anyway, I came here to address some possible nuances with oversimplified models like DeMarre(but also Thompson’s and Krupp formulas): they are, in essence, approximations, valid only for a given range of values of thickness and striking velocities. They inevitably break down and start giving unrealistic results once we go too far.

Here is what I mean: here is a comparison of accurate Thickness vs. Ballistic Limit(Navy) curve build from experimental data of 76mm M79 AP and a rudimentary model, like DeMarre’s equation (but not the actual DeMarre equation, mind you) fit to match the data. As you can see below about 0,5 calibers thickness it starts to deviate more and more, despite giving excellent fit for higher thicknesses.


Which is not to say that what you’re trying to do (to design a relatively simple and accurate model for terminal ballistics) is a lost cause, just that there are some kinks to be aware of.

I’m aware of the limitations. I’m not trying to create a historically accurate simulator. I’m trying to create something reasonable that is simple to explain and simple to implement for Gaijin.

If they fixed AP British tanks would become half decent. They cant have that.

It would make a lot of tanks better. I know this isn’t as fun as new vehicles or new maps but it would have a significant impact on game play.

On the topic of how much penetration AP cap steals from the round:


The ratio between BLs is almost constant and equal to +5% for the capped shell, relative to uncapped shell of the same mass as penetrator w/o cap. (M62 w/o cap and windshield, but filled and fuzed should weight 12.64lb.)

Edit: It appears that this effects is greater when obliquity is increased from 0° to 20°, but the sharp drop at 30° against thick plate is difficult to explain.


From canadian data, it appears that the capped shell has a fixed +8,5% increase in critical velocity both at 0° and 30° angle:



The 5% checks out, according to my calculator suggestion.