Yearly rant about western allied AP and HVAP ammo

[FlipAllTheTables]

@BadOpinionHaver

17pdr AP should pen the front of a Panther at 500m

According to Nicholas Moran (“The Chieftain”), this Panther was seemingly hit first by 5 APDS rounds.

To demonstrate this, an impromptu test firing was conducted at Balleroy, in Normandy, against a captured Panther tank. US First Army was provided with a British 17pdr, with new APDS (discarding sabot) ammunition. There was no formal report or minutes written from this test firing. However photos of the results were routed through US field commanders in Normandy. The results were summarized in a subsequent report:

… in firing conducted by First U.S. Army at Balleroy on 10 July 44, 5 rounds were fired at the front plate of a Panther tank at 700 yards. Examination of pictures of this firing indicates that the first round struck the mantlet, the second between the track and the nose plate, the third at the junction of the nose and glacis and penetrated. The fourth and fifth were fair hits on the glacis and both penetrated.

Panther before additional shots cracked the plate

Not only does it explain the seemingly smaller holes, but it also explains why they are so “all over the place”, as APDS for the 17 pounder was notoriously inaccurate.

The hit marked with an arrow that says “17 pounder” is more likely to have been a normal AP round. But not only was the armor of this Panther of seemingly lower quality (after all, catastrophic failure after relatively few rounds), but the upper glacis had already been hit and penetrated by APDS rounds. The hit marked with “17 pdr” seems to coincide with a crack which would back this up further.

All that said, I heavily doubt normal AP rounds would go through an undamaged Panther glacis that isn’t of low quality, and generally allied documents agree.

[MyceliumActivist]

Fair point. I sometimes wonder if the German heavies should get an 0.9x armour modifier vs full bore rounds to represent the poor characteristics of their face-hardened steel.
Here is a photo of a Jumbo transmission hub after surviving a lot of fire without failing. Ironically, the Jumbo gets the 0.95x cast modifier in game.

[scorpian]

I just really want Gaijin to have the T33 perfom as it should to deal with all the Panthers, Jagdpanthers and Panzer IV/Vs.

Having the 90mm, which is a common mid tier gun for the US and other nations, able to engage the cats without resorting to HEAT would only benifit.

[FlipAllTheTables]

@BadOpinionHaver

Fair point. I sometimes wonder if the German heavies should get an 0.9x armour modifier vs full bore rounds to represent the poor characteristics of their face-hardened steel.

There has to be a balance between realism and gameplay. This is unnecessary as long as their tanks are balanced for the BR they are at. If their armor becomes worse… then you can expect their tanks to go to a lower BR as well.

Besides, german late war tanks had a 0.85x multiplier (at least that’s the value I remember right now) for their armor way back. It’s been removed for good reason.

@scorpian

I just really want Gaijin to have the T33 perfom as it should to deal with all the Panthers, Jagdpanthers and Panzer IV/Vs.

I understand frustration about it, but I’ve also simply come to terms that it won’t happen. Gaijin is resolute on not changing the calculator or formulas for basic AP rounds. Besides that, M82 is still a very powerful round, and the 90 mm cannon has the only “good” APCR round in the game.

The Panzer IV/70(V) upper glacis will provide ~164 mm of effective protection against M82, which means it can be penetrated well within 500 meters, potentially even at 800 meters. The lower glacis on the transmission is a lot easier to penetrate and M82 is actually strong enough to go through the transmission and kill both driver and gunner, potentially the commander as well.

Panthers and Jagdpanthers are more difficult. M304 can penetrate the UFP straight on up to about 250 meters in WarThunder, which is relatively small use case but I can confirm it works. It even deals decent damage.
The LFP can be shot with M82, and if you shoot below the transmission it will generally one shot, and there’s the machinegun port. Both of these shots work better for normal Panthers, as the Jagdpanther has had its armor reworked.

https://streamable.com/8ifvle

If you want you can shoot the LFP with M304. It will penetrate through the transmission since it doesn’t explode, and you can take out driver and gunner with a well placed shot.

[TyTheGuy27]

@BadOpinionHaver

I sometimes wonder if the German heavies should get an 0.9x armour modifier vs full bore rounds to represent the poor characteristics of their face-hardened steel.

I don’t think so. All vehicles should be modelled assuming “ideal” construction. Otherwise, other tanks (T-34s for example) would need their bad weld quality modelled, and others faulty transmissions, overweight suspensions, and on and on. It’d be an absolute nightmare for implementation and balance. Same with aircraft, which should have jet engines exploding when throttling too quickly or afterburning too long.

[MyceliumActivist]

@FlipAllTheTables

This is unnecessary as long as their tanks are balanced for the BR they are at

Well, hopefully that happens someday. As it stands they’ve absolutely dominated tier 3 and 4 since I started playing. Panther D now below the Jumbo in RB. But I agree that armour quality modifiers would be unpopular so I doubt it’ll ever happen. Maybe that’s a good thing, idk.

@TyTheGuy27

All vehicles should be modelled assuming “ideal” construction. Otherwise, other tanks (T-34s for example) would need their bad weld quality modelled,

Fair

[scorpian]

@FlipAllTheTables

The Panzer IV/70(V) upper glacis will provide ~164 mm of effective protection against M82, which means it can be penetrated well within 500 meters

Only below the drivers port on ranges of up to 500m and above, making a still risky shot. Shooting the transmission is also a gamble because sometime the game just decides that itll absorb the blast and shrapnel even if you aim for the right or left corners.

LFP shots are possible but a huge gamble to pull off. Any deviation and your blasted back to the hanger.

Ill also mention that ive seen a lot more complaints about players grinding the US tree hitting the 5.7-6.3 bracket. Mostly in regards to engaging cats in situations where flanking is not an option. Since the T33 cant perform the US and other nations that rely on mid tier 90s are stuck trying to pidgen hole Panther turrets and Jagdpanther LFPs.

With poor success.

[FlipAllTheTables]

@scorpian

Only below the drivers port on ranges of up to 500m and above, making a still risky shot.

You could also shoot nearly the entire right side of the tank with M82. Still, even the areas of the upper glacis that have track armor can be penetrated up to 300 meters with M82. Track armor is hard coded to a maximum protection value of 15 mm (that took me a surprising amount of testing to figure out).

With M304 you can penetrate to a longer distance, seems to be 700 meters. It’s hard to determine exactly the distance where M304 reaches a 50% chance, due to APCR/early APDS losing penetration due to shattering against multiple plates of armor, and that not being shown in protection analysis. When (and most importantly if) I figure out how the math behind it works, I’ll be able to determine that distance much more accurately.

[SpardaSon21]

@scorpian

Mostly in regards to engaging cats in situations where flanking is not an option.

And with Gaijin making maps smaller and smaller this is only going to get worse and worse.

[Ford1639]

Yes, this needs to be fixed. The American t34 & t29 can’t pen the front is outrageous.

[Ford1639]

If their armor drops, why would they get lower BR? The T-series USA tanks can get penned frontally by the tigers and panthers- yet it’s the same BR. But the T-series can’t pen their hull.

[Zyranovos]

The major player isn’t the fact that the shell is able to pen it (it isn’t) because all gaijin’s maps are knife fights for the most part, and therefore, there is no shell arc, the arc changes the angle of contact when engaging, so in other words, the longer range/higher arc, it means your going to have a higher pen chance, considering the panther in question is a production run “D” the 80mm front plate will act more like 90-100 ~ LOS allowing a shell to go through. This also goes vise-versa. So, in an essence, yeah, this is most certainly correctly modeled in game.

[FlipAllTheTables]

Simply put, no.

Bullet drop is not nearly meaningful enough in either real life or WarThunder for that to actually work that way. To achieve that 90 to 100 LoS you are talking about, the hit would have to be at around 35°. That is a 20° bullet drop which is absolutely insane. To put that into perspective, the Sturmpanzer with it’s 150 mm Howitzer and subsonic rounds reaches a bullet drop of around 5° at 800 meters. Now we are dealing with rounds that go 800 m/s at the very least, so bullet drop becomes completely meaningless.

There are quite a lot of things that point towards the fact that these rounds were simply capable of going through a Panther’s upper glacis. First off, simulations.

M36 JACKSON vs PANTHER | 90mm T33 APBC Armour Piercing Simulation

In this first simulation we see T33 APBC being just about capable of defeating 80 mm at 60°. Any bullet drop that might perhaps be in this simulation (which at 200 meters would be basically none) is more than overcompensated by the much higher angle.

PERSHING vs PANTHER | 90mm M304 Hyper Velocity Armour Piercing Simulation

This second simulation is with M304 HVAP. This is a clean 80 mm at 55° degree penetration, not much else to be said.

Bullet drop very clearly isn’t the reason why these rounds perform how they do. That brings us to the second part which is actual US ballistic limit testing, using a long 90 mm cannon firing T33, T50 and M304.

Ballistic Limits

There’s a lot of information from this table. For example, T33 can defeat 4 inches (101.6 mm) RHA 280 BHN at 55° with a velocity of 2742 ft/s (836 m/s). It can also defeat 3 inches (76.2 mm) RHA 280 BHN at 60° with a velocity of 2629 ft/s (801 m/s), and BHN 320 with a velocity of 2645 ft/s (806 m/s). These last two values line up very well with the first simulation, in since there T33 has a velocity of 822 m/s.

There’s no 3 inch RHA plate at 55°, sadly, so we will have to make do with the CHA plate with 280 CHA at 55°, which is defeated with a velocity of 2313 ft/s (705 m/s).

If we were to look at a velocity graph for T33 (such as the one in “Terminal Ballistics Data, Volume III”), we can see that T33 fired from a normal M3 90 mm cannon achieves a velocity of 2325 ft/s at 1800 yards (1646 meters), marked by red lines in the spoiler below. Of course, this is once again CHA, rather than RHA, and it is also slightly thinner than an actual Panther, so the penetration distance is expected to be higher than what would be expected. Additionally, the ballistic limit table doesn’t quite state what penetration criterion is used.

However, TBD V3 does state RHA penetration values for T33 at an angle of 55°, specifically with Navy criterion which is what WarThunder emulated. Using it, it says that T33 defeats 80 mm (3.15 inches) at a velocity of roughly 2500 ft/s (762 m/s), which means a range of roughly 1250 yards (1140 meters), this being marked in green.

Terminal Ballistics Data, Volume III

[Zyranovos]

Alright, that’s definitely believable, considering the furthest engagement I’ve heard of was 800-900 meters, depending on the shell and ballistics, yeah, considering that, simply put 80 mils isn’t a lot, isn’t surprising, but, the Panther F has 100 mil armor from what I remember. Also, Strv 103’s sloped armor at roughly 70° can bounce a T-10M’s APHE, remember the fact it’s only 40 mils of armor. I feel like it (panther) should be a bit more protected than that, but maybe not.

[Mytho-GR1]

Yeah imperfections cant be modeled imagine in their was a chance when you spawned in your T34 your sight was just terrible and to see wouldn’t be fair

[FlipAllTheTables]

@Zyranovos

the Panther F has 100 mil armor from what I remember.

Panther F only changed the turret, the hull is still 80 mm. It is only the Panther II that has a thickened upper glacis.

@Zyranovos

Strv 103’s sloped armor at roughly 70° can bounce a T-10M’s APHE, remember the fact it’s only 40 mils of armor.

T33 APBC (and basically every other US APBC round) were made specifically because the US found that uncapped AP rounds were superior to capped AP rounds when facing highly angled armor where the projectile’s diameter is bigger than the armor plate thickness. In fact, that is pretty much one of the conclusions of the first source I used.

Data on the comparative armor penetration performance of kinetic energy projectiles of the AP, APC, and HVAP types are included in Table I. This table compares the penetration performance of the 90MM AP T33, the 90MM APC T50, and the 90MM HVAP M304 shot when fired at cast and rolled homogeneous and face-hardened armor from 3" to 7,6’’ in thickness at obliquities of 30° to 70°. The comparative performance of these kinetic energy projectiles against solid armor targets may be summarized as follows:

a. Monobloc steel shot are more effective than capped steel shot for the defeat of undermatching armor at all obliquities of attack and are more effective than both APC and HVAP shot for the defeat of moderately overmatching armor (up to at least 1-1/4 calibers thick) at all obliquities of attack above approximately 45°.

In this quote, “overmatching armor” is when the projectile caliber is lower than the armor plate thickness. And “undermatching armor” is when the projectile caliber is higher than armor plate thickness.

Basically this paragraph just says that if the uncapped AP round is larger than plate thickness, it just better than the capped AP round.

[AurenKarach]

@BadOpinionHaver

I sometimes wonder if the German heavies should get an 0.9x armour modifier vs full bore rounds to represent the poor characteristics of their face-hardened steel.

That sort of thing doesn’t really belong in War Thunder imho. Should T-34s have no access to third person camera because they lack a cupola?

IMHO gameplay always comes before realism. You could easily say that if you really wanted all those historical modifiers, then you should have historical lineups as well. Good luck making that work…

Also, people always assume that BRs would stay the same after changes like these. No, they would change.

Careful what you wish for.

[FlipAllTheTables]

I want to say, I actually messed up when using “Terminal Ballistics Data, Volume III” for T33 APBC.

When making the green line, I connected the penetration directly to the velocity, rather than to the 55° curve, which then connects to the velocity line and distance.

As such, the actual velocity at which T33 penetrates 3.15 inches (80 mm) of armor is somewhere between 2425 and 2450 ft/s (739 and 747 m/s respectively), with a distance of 1300 yards (1190 meters). However, there’s a source called “Armor-Piercing Ammunition for Gun, 90-mm, M3”, which has velocity values that disagree with TBDV3.

Corrected graph

This is how it was previously.

However, as I said, penetration values connect to the angle curves to the angle curves, which then connect to a velocity value, which isn’t what I’ve done here with the green lines (red lines are still correct however).
These are the corrected results.

As stated, the corrected values say a velocity between 739 and 747 m/s rather than 762 m/s I said previously, which also means a longer distance of 1300 yards (1190 meters) rather than 1250 yards (1140 meters). However, the other source I have mentioned (“Armor-Piercing Ammunition for Gun, 90-mm, M3”) states that at 1400 yards (1280 meters), T33 reaches a velocity of 2431 ft/s (741 m/s), which just so happens to fall right between the two velocities given from TBDV3.

I do think these values are a bit optimistic, likely lower BHN plates. T33 would still definitely go through a Panther’s UFP anywhere from 0 to 1000 meters though.

[Jarms]

Ammunition as a whole needs to be reworked.

• Penetration calculator needs to be adjusted.
• APHE needs to be nerfed. It shouldn’t explode like a grenade, just a slightly bigger cone compared to solid shot.
• APDS needs to be better against slopes and shatter less.
• HESH needs to work similar to HE again, but with far better penetration and performance against sloped armour.

[Fluffy_Bucketles]

Real rough on the 17pdr. Struggling to go through easy tanks, APDS shattering on flat surfaces, solid AP failing to go through the sides of tanks for some reason. Rounds doing nothing in the event they do go through (Which is inaccurate, regardless of if it has HE filler or not).

Shit’s just rough.