Body Armor Penetration of HP/HPBT < FMJ/Ball < AP are inverted to HP/HPBT > FMJ/Ball > AP

[DJ-Reticuli]

Mods (complete and add to the following information):

• Arma 3: x.xx [e.g. 1.00 stable, rc, dev]
• CBA: 3.x.x [e.g. 3.0.0 stable, commit hash]
• ACE3: 3.x.x [e.g. 3.0.0 stable, commit hash]

Arma 3 v2.08
CBA 3.15.8
ACE 3.15.2 (also tried 3.15.0, same issue)

Description:
A clear and concise description of what the bug is.

In ACE Virtual Arsenal testing body armor, very clearly AP is penetrating less than ball/FMJ.

This is the reverse of what several iterations prior to these versions did, which I had tested thoroughly ending on 9-25-2022. After that at some point I updated to the latest Arma 3 that broke the thermals, so I eventually reverted to the old v2.08 and the accompanying versions of CBA & ACE that v2.08 require. Clearly the body armor penetration flags (or their handling) for different ammo types is inverted, though, at least for 7.62x51. I cannot revert to an older version of Arma 3 equivalent to what I was using 9-25-2022, though, so I'm stuck with these versions of CBA & ACE.

Steps to reproduce:
Follow this flowchart!

1. Have just CBA & ACE in use as mods
2. Go into ACE Virtual Arsenal
3. Put on body armor and equip an M14, with the default ball, AP, and HPBT in your inventory.
4. Take some shots at the plates and check the effects with Ace Medical.

Expected behavior:

Armor penetration: HP/HPBT < FMJ/Ball < AP

Where did the issue occur?
ACE Virtual Arsenal

Log Files:
There was no crash, so there's no point in this.

Additional context:
This may have been fixed in subsequent ACE, so if so and you can test and confirm it's no longer an issue, great.

In prior versions of Arma 3, CBA, and ACE, this is what I had documented:

https://steamcommunity.com/sharedfiles/filedetails/?id=2868465442

At least in ACE Virtual Arsenal in the versions I'm using, it's flip flopped for some reason.

Obviously the frangible SD rounds should penetrate even less than the hollow point rounds (and not even cycle), but that's another issue. The SD mag is so low velocity, it's not really relevant to this particular glitch above.

Screenshots:
Not applicable.

[BaerMitUmlaut]

Arma 3's body armor simulation is extremely limited. It's basically just a damage reduction, there is no such thing as armor penetration simulation on units, which is why you get such strange effects.

[DJ-Reticuli]

Ok I get that it's simplified, but previously it worked somewhat when the M993 rounds from ACE did more against armor than ball/fmj. For some reason now it's exactly the opposite. The issue with AP vs ball seems to date back to sometime around the end of 2022 when ACE bullet values or the math using them in Arma 3 + ACE damage reduction seems to have changed. When I tested it in 2022, the M993 caused more damage to armor-wearing soldiers than the ball/fmj rounds, and later in 2022 that appears to have flipped in reverse, where now the M993 causes the least damage when they're wearing body armor. I have eliminated the possibility that it's other mods as this happens when just using CBA & ACE as the only mods. Prior to some change, I am confident the M993 dealt more damage to units in armor than the standard M14 mag.

Interestingly, the M118 LR rounds (which are boat tail hollow points) are causing damage to soldiers in body armor to a bizarre, over-blown degree the most, like you're hitting them with a 338 or even 50 cal, but the issue with ACE hollow points was a pre-existing problem. Obviously, it should be AP is better against armor but worst against unarmored, HP is worst against armor but best against unarmored, and ball/FMJ is in the middle. Some of that (AP vs ball/FMJ) seemed to work before, while the hollow point stuff was always problematic, but now it's all goofy and curiously in the exact reverse of what it should be.

By the way, in the meantime is there any way to disable all the added ACE ammunition while keeping the rest of ACE including medical and ballistics?

[LinkIsGrim]

Ok I get that it's simplified, but previously it worked somewhat when the M993 rounds from ACE did more against armor than ball/fmj.

Placebo effect. Only thing that affects damage is hit on the ammo and impact speed matching typicalSpeed. M993 has always had a hit value lower than even B_762x51_Ball.

By the way, in the meantime is there any way to disable all the added ACE ammunition while keeping the rest of ACE including medical and ballistics?

You can just not use magazines with those ammo types.

Shameless plug: #9217

[DJ-Reticuli]

Ok I get that it's simplified, but previously it worked somewhat when the M993 rounds from ACE did more against armor than ball/fmj.

Placebo effect. Only thing that affects damage is hit on the ammo and impact speed matching typicalSpeed. M993 has always had a hit value lower than even B_762x51_Ball.

By the way, in the meantime is there any way to disable all the added ACE ammunition while keeping the rest of ACE including medical and ballistics?

You can just not use magazines with those ammo types.

Shameless plug: #9217

Wow, in non-ACE, 'caliber' dictated penetration. In ACE, 'ACE_caliber' is the physical caliber and appears to be part of the ballistic calculations, and the original 'caliber' value appears to be completely ignored, hence why with ACE, penetration seems entirely dependent on just the 'hit' value, which is why the results against body armor now are often opposite of what they should be.

Either they need to start utilizing the non-ACE caliber again for penetration calculations and/or utilize another method. I suggested another method in the shameless plug link you posted.

[BaerMitUmlaut]

That's not true. Please stop spreading made up misinformation.

[LinkIsGrim]

+1, caliber property doesn't affect armor penetration on infantry (gross oversimplification, it actually does and I have a rant on this on the discord somewhere, but it's not the way you think)

damage is (impactSpeed/typicalSpeed * hit) / hitpointArmor, the end. both in vanilla and ACE.

[DJ-Reticuli]

The hit values on ACE 7.62 NATO ammo are still stupid inflated, but I mitigated the rest.

https://github.com/acemod/ACE3/discussions/11028