As requested a quick and brief Bit of Armor on the shell characteristics in World of Warships and World of Tanks. Let’s stick to the two most basic ones: AP and HE.
HE and AP – WoWs
Generally HE does less damage to targets but cannot over-penetrate weaker targets and thereby guarantee damage. This type of shell is also the only shell that can cause fires to ships.
AP shells need to penetrate in order to do damage; there is a fuse that kicks in after penetration, causing the shell to explode inside the ship. There is no 25% RNG on penetration value as it is on WoT, but will lose penetration over distance. A trick for shooting AP is to do at it very long range, since the flight path will let the shell fall in pretty much vertical, hitting the ship’s deck, rather than the ship’s side (“plunging fire”). The deck is of course easier to pen. There is an over-penetration risk, meaning the shell will exit the target, without being able to do a critical hit. Metaphor: compare it to sticking a needle (AP) through a pack of butter (weakly armored target) compared to ramming your fist (HE) on the butter. The fist will cause a more blunt impact, doing more damage.
In short: Use AP against armored targets you can pen, and HE to targets that have low armor values. HE shells will cause little to no damage to heavily armored targets.
HE and AP – WoT
WoT does not allow overpenetrating shells, hence always doing damage when penetrating. There is a 25% +/- RNG on your average penetration for both shell types as well as in damage values. In War Thunder you have APCR causing less critical spalling since there is once again a needle (APCR) piercing the armor, rather than a nail (AP). The more focused energy of APCR gives it more penetration, but less spalling. In World of Tanks this effect does not exist; both will damage on penetration.
In both games the angling of the armor affects penetration capabilities.
So, to keep it short I will end it here. Feel free to add your additions in the comments and let the tips and tricks be shared! Thanks again. Let me know if you would like to have a topic covered in the next Bits of Armor.