30mm Performance Discrepancy


So, what’s up with this?

I sampled four 30mm APDS rounds, three with very uniform performance and one with significantly more variation.

My original intention was to prove that the 3UBR8 was overperforming at range and maintaining too much energy/pen (it is), but I found that there is a significant discrepancy in the performance of the RARDEN APDS vs its contemporaries in terms of energy loss.

Now I’m all about realism, but I know we do the best estimate with the information we can here. There are various semi-arcane formulae and calculators involved, but in general we’re seeking to emulate the real-life performance to some degree.

So why is this round so different from the others? Why does it lose over 60% of its energy over 2000m when its contemporaries lose around 10-15%?

Floor’s open man, I’d like to see some explanations.


Oh no he has done it


honestly look at how good the fox is doing at 7.0 with the same gun as Warrior just from people not learning how to not get flanked. I don’t think gaijin wants the warrior to be competitive at all and it would also seriously buff the fox, which would make then entire german main player base revolt

Fox’s current performance is a combination of firepower and mobility, compounded by the low mobility of the vehicles it faces at 7.0. I see it going up to 7.3-7.7 fairly quickly but that’s a conversation for the FV721 Fox thread.


I agree its not for this thread but it has been very very amusing getting insulted in chat by players that are tunnel visioning points while I drive up to them in open ground

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The only way I can make sense of this is to look at the weight and initial velocity of the shells. In this case, it should be the warrior has a high velocity, low mass projectile relative to the other shells.

i think it has to do with the differences between air resistance of APDS-T and APFSDS. one being shorter and fatter than the others.

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I think he is talking about this:


Almost no penetrtion drop-off from 10 to 2000m.

And then there’s 35mm APDS:


Or Fox/Falcon/Warrior 30mm APDS that loses half the penetration:



Which in itself would be fine

If Gaijin gave that treatment to every autocannon calibre APDS round. It doesn’t. Not clearly anyway.

There’s talk of some magical formula but I don’t see how you’re going to get such a drastic drop off in Penetration when they’re all roughly the same calibre, probably similar masses and materials, and similar velocities?

Both 3UBR8 (BMP-2 APDS) and L14A2 (Warrior APDS) are approximately 300g.

3UBR8 muzzle velocity is 1120m/s, while L14A2 is 1175m/s ingame, both values are correct.

Thanks, then the only other logical thing I can think of is it’s losing a lot of speed at longer ranges (higher drag). I would have to check if the Brit apds has a larger drop over distance.

I can provide you sources for both;

  1. The penetration requirement of L14A2 is 40mm @ 40° @ 1,500m, and this is repeated in every secondary source.

  2. The advertised penetration of 3UBR8 is 25mm @ 30° @ 1,500m according to Rosoboronexport, the state ammunition exporter.

Otherwise the velocities are only marginally different, the weights are almost identical, so I predict that it comes down mostly to the material composition of the projectile.


They have pretty much the same drag coefficient in game. The Reason for the difference is the HS831 APDS (which is incorrectly copied to become L14A2) isn’t using Demarre Formula for penitration.
Here’s a table of all the Auto cannon APDS I can remember and some of the datamined values

There’s some duplicated data only because gaijin can’t do things the same between different rounds
(and some larger cal APDS for a table I’m working on)

(also yes 20mm DM 23 doesn’t have a drag coeffient, I checked all the RH202s lmao)


That would certainly explain it, I was under the assumption it was following the formula.

As far as I can tell, It’s the only round still using the old look up tables

So it would have the same penetration performance when using De Marre?

No, it would presumably have some ahistorical rubbish behaviour that didn’t obey the laws of physics, with more similarity to a laser beam than a projectile.

No idea, we don’t actually know enough about L14A2 to come to any conclusions, only that it can penetrate 40mm of armour at 45 degrees (~50-55mm LOS by my 0200 in the morning napkin math which roughly lines up with whats in game) at 1500m, and we know its a relatively early APDS so angled results are a little funky.