Can DR be negative?

[Mado]

Like in a subject. Can DR be negative using for ex. AP ammo? Take for instance 10mm AP ammo with DR mod -35 and enemy without armor. After calculating DR is equal -35 % or 0 %? If the first case will be true, does it mean that the overall DMG output is equal 135% of the base value?

[Kirkor]

It is better to use JHP ammo on unarmored targets.

[VVish]

Example:
If enemy resistances are 0% and you're using 1\1 dmg -35% dr mod ammo, resistances will still 0%, they're not going below 0.

If enemy resistances are 15% and you're using 1\1 dmg -35% dr mod ammo, resistances will be 0%.

If enemy resistances are 15% and you're using 2\1 +20% dr mod ammo, resistances will be 35%, but damage will be doubled.

So, basically, JHP (the one that multiplies damage) is good to use against low- or un-armored targets, AP - against armored.

[Chosen One]

AP has never worked for me. Always seem to get more out of JHP (slugs for shotguns) than I can out of AP, short of power armor.

[Mado]

Thanks for replies! According to information given by you, we can do some calculations! Let's take a case when target has the best armor possible to find in game the Power Armor (40 DR and 12 DT) and our weapon will be Assault Rifle (14-23 DMG) that uses both 5mm JHP (DRmod +40% and DMGadj 2/1) and AP (DRmod -35%
 DMGadj 2/3) ammo. We are taking the worst (well maybe not the worst but worst when taking the dmg) scenario possible, we rolled 14 DMG with assault rifle with both shots taken, both following JHP and AP ammo.

So JHP case:
Base DMG = 14. DMG * DMGadj = 28. *hits target*. DMGoverall - DT  = 16. DR = 40 + DRmod = 80;

100 - 80 / 100 = 0.2; // The 100 % - 80 % damage = 20 %

DMGoverall * 0.2 = 3.2 DMG

Now AP case
Base DMG = 14. DMG * DMGadj = 9.3(approx). *hits target*. DMGoverall - 1/3DT = 5.3(approx). (1/3DT Because of penetrate perk for that type of ammo)
 DR = 40 + DRmod = 5;

100 - 5 = 95%

DMGoverall * 0.95 = 5,035 DMG

In that case AP ammo is better.
Let's take Brotherhood Armor now, values for: JHP =  4; AP = 6.3;
Take CAMK2 values for: JHP = 4.4; AP = 6.9;
Take CA valuse for: JHP = 4.6; AP = 7.25

JHP is getting way better when used on armors below CA's
Metal Armor: JHP = 9.1  AP = 8.6;

Conclusion: Use rockets or Plasma even better!

After that random pile of senseless calculations we know that the AP ammo is better (who was expecting so spectacular results!) and again thanks for replies.

[Chosen One]

Plasma and rickets destroy the armor.