No, just a feeling.
Something like the: As the diamter increases the weight of the cap increases exponantially, or something like that.
Well so does the rest of the round, isn’t it?
It all gets increased at roughly the same rate, all by the same percentage, wouldn’t it?
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Probably. But I think that AP shells might get too heavy, when you upscale them.
I think bigger shells are generally shorter than small shells.
Ah, I see your reasoning. Yeah true, after a certain point, higher caliber shells are made shorter to keep weight manageable for the loader. But assuming the cap mass is the same for a given caliber, regardless of how long the rest of the shell is, it will take up progressively more mass, percentage wise, of the total.
But I still don’t think it would have any additional negative effect besides that.
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I think you’re right.
The 76mm M79 is 6.8 kg. The 120mm M358 is 23.1 kg. If the 76mm was scaled to 120mm, it would be about 26.8 kg.
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while we’re on the topic of AP caps. Sounds like an interesting read. https://apps.dtic.mil/sti/tr/pdf/AD0029525.pdf
At this velocity this shell should penetrate up to 40mm of vertical armour. 40mm/9.52mm = 4.2 slope multiplier at 70° angle. This indicates that the glacis plate of the Pz.IV (20mm/72°) would provide equivalent protection in excess of 84mm/0° against small caliber (37mm or 40mm), high quality AP shells.
Can someone check whether the 2pdr penetrates this spot in the game?
Edit: the graph I previously posted was wrong. Here is the correct version.
This is based on factual testing data with steel and tungsten projectiles with various head radii.
As we can see, the german 1.1 CHR 7.5cm Pzgr.39 is expected to have 4% less vertical penetration than an otherwise identical shell with a 1.4 CHR head, characteristic of the british AP.
On the other hand, the core of the .50cal AP bullet, with it’s extremely sharp 5 CHR nose, will penetrate an impressive 16% greater vertical armour thickness.
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Is there any data for sloped penetration with the various head radii?
I have some:
Note that the angles here are in German notation. “30°” is 60° angle as we usually define them.
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That’s interesting. The T33 and T50 have 1.5 CHRs but the ogive is secant instead of tangential.
Same with pointy German 20mm AP that really sucks vs. 30° but is very strong against flat armor.
This projectile has only a 2 CHR nose, not enough to make a significant difference due to it’s shape. It does help it stay intact at 0° against thick armour.
Most of the difference between 0° and 30° pen is due to this shell shattering easily against 30° armour, because of a combination of it’s sharp nose, high hardness of the armour of this gauge (20-30mm) and lack of AP cap as well as restrictive german penetration criteria.
Everything works against it here.
NPL formula generally gives accurate predictions, except for below 1600fps ( < 1 caliber plate) and beyond the point where shell w/o it’s AP cap starts to deform from impact.
There’s some truth behind it but Gaijins implementation makes just no sense, since a lot of penetration power comes from the overall weight of the shell, instead of just supplementing the core.
If the core is light, while the shell is relatively heavy, like Soviet 76mm or 85mm APCR, the shell mass should increase the penetration beyond the cores performance.
But the current system greatly underestimates the performance of the core by itself, thus making most APCR rounds less effective.
M332 APCR in-game is fired at much higher velocity than M304, yet they have practically the same armor penetration, since M304 is heavier, completely negating the higher velocity of the lighter M332, which should penetrate a T-54s turret like butter.
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APCR is included in the changes.
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But just considering core weight wouldn’t give accurate figures for some APCR rounds.
Sure, but Gaijin isn’t going to that level of detail with its formula. They don’t even use the correct core diameter and weights for some rounds.
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What do you mean? They are doing it right now. They use the total weight and the core weight with way too much emphasis on the projectile weight, which results in heavy cores underperforming.
Best example is the M41A1 which has an APDS and APCR with the same core, yet the APCR gets 220mm pen while the APDS gets 300mm pen, since APDS doesn’t use this shell mass + shell core system.