So the BR-367 is in the ballpark. I figured the BR-365 and 365K would be off. The document I used for BR-365P listed 130mm at 1000 meters but was in English, so it may have been wrong. I’ll see if I can adjust that.
I just realised a thing that this formula can be quite useful in exam😀
Honestly I felt like the penetration for the APCR was a bit too high before, at over 200 mm when point blank. The core is just super small and I can’t see how it would actually get close to US 76 mm APCR.
This was only reinforced by simulations like these where BR-365P barely goes half way through the armor of the Tiger II (H) turret front from just 180 meters. The new values you’ve provided seem very close to what this simulation says.
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Yeah, I did do. It had to be that high to match this document but it must be wrong.
I am copying and submitting this as a suggestion. Just need to get approval.
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So, the reason for this is that Gaijin cherrypicked a Russian source that implied that a lot of APCRs penetration comes from the carrier transferring energy to the core during penetration, similar to how you’d expect composite APFSDS rounds to work. This informed their APCR calculator.
Obviously this source is just flat out wrong and this is only there to benefit Soviet APCR, which had big heavy carriers and were generally less advanced.
IIRC this source isn’t even really available on the English language internet anymore, it was on some Russian language forum a long time ago (maybe Otvaga?) but I can’t remember what it was called.
I believe I’ve seen the source you are mentioning, as I vaguely remember reading a description of the inner workings of an APCR round that talked about how the jacket of the APCR round would impart it’s kinetic energy into the core when penetrating armor, alongside this image.
Spoiler
Personally I don’t think this makes much sense, at least not to the extent that it is represented in the game. The jacket is far wider than the core, so before it can even impart its energy into the core, it has to go through the armor that it is hitting, so a lot of that “additional energy” would be wasted on even trying to reach the core.
My adjusted APCR formula doesn’t use carrier weight. Ignoring carrier weight actually gets it closer to Soviet documents that Conraire shared.
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Soviets had some pretty lackluster APCR. So it does seem strange that more advanced HVAP/APCR is bound to the rules of the weaker Soviet counterparts.
I’m pretty convinced the whole calculator system is based on Soviet rounds.
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So how would this change to the APCR calculator impact smaller shells like the 30mm PGU-14/B, used by the A-10 / GPU-5/A gunpod?
Info for the PGU-14/B and performance data can be found Here and Here
I’m not sure how the DU penetrator would perform compared to a tungsten carbide core but my suggested calculator gives 148mm at muzzle velocity.
Can you calculate the penetration of the M321(T29E15) HVAP? Same dimensions as M319, with MV of 3775 fps. This projectile is authorized for 76mm guns M1A1, M1A1C, M1A2 and T94.
M321 comes out to 262mm.
M319 comes out to 290mm.
From what I know, DU erodes instead of fracturing and shattering like WC. This decreases flat penetration but improves penetration against angled armor, at least that’s how I understand it working to the best of my ability.
DU APCR rounds like those on the GAU-8 and the LAV-AD’s 25 mm in WarThunder use their own slope modifiers which are superior to those of normal APCR to reflect this. But then they have their own calculator variables, separate from those of normal APCR, specifically to achieve lower penetration values.
I imagine you’d have to make another calculator for DU cores.
Yeah, I knew the two types behave differently. The formula i based my suggestion on is for early tungsten carbide cores. It won’t work for tungsten alloy or DU.
Here’s how the 76mm M1A2 would look with M321 HVAP and T166 APBC. This would be nice for the M4A3 and M18 at 5.7.
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Support my suggestion to get these changes implemented.
Regarding the DU core HVAP, current calculation gives pretty much a correct value.
- PGU-20/U
Penetration data of the PGU-20/U is listed in the NWP 3-22.5-AV8B, Vol. II.
For 2.5 inch RHA at vertical impact, V50 (The velocity at which 50 percent of the projectiles will penetrate the target) is 3368 fps. Current penetration is 66mm at 1036 m/s(3399 fps).
- PGU-14/B
You can find the penetration graph for PGU-14/B here.
Penetration on 300 BHN plate, at impact velocity of 980 m/s and impact angle of 30 degree, is 73 mm. Current value is 68 mm. It is slightly low but acceptable.