Differences in tank ammo types.

Ammunition is the basic firepower of every plane or vehicle, whether it be offensive or defensive in utilization. All aircraft and ground units in War Thunder use ammunition to some extent. On this guide i'm going to talk about tank ammunition.

Armor Piercing (AP)

A solid, pointed, steel shell that is of the same bore diameter as the barrel. It penetrates well but relies on the shell and spall to do the damage to the tank and crew.

Armor Piercing Capped (APC)

Same as above but has a soft, blunt cap on the tip. This allows the shell to normalize when it hits armor. Normalization is the ability of the shell to try and achieve a normal (90 degree) angle to the surface of the armor. This increases penetration and reduces the ability for the shell to ricochet. Damages just like plain AP.

Armor Piercing Capped Ballistic Capped (APCBC)

Same as above but an extra (thin and typically hollow) cap is put over the blunt cap. This make the shell more aerodynamic and allows it to be more accurate, hold more velocity over range, and therefore penetrate slightly better.

Armor Piercing High Explosive (APHE)

This can be either of the above previously mentioned AP types (AP, APC, APCBC). It's either of the AP shells mentioned above but with a high explosive filler and a tail fuse. These penetrate just like their non +HE counterpart but when they pass through a certain thickness of armor (in mm) they set off the fuse and detonate sending shrapnel into the crew compartment.

High Explosive (HE)

This shell is thin-walled and contains a large amount of HE filler. The fuse is on the nose of the shell and detonates when it contacts a hard surface. These do not penetrate well and should be of limited use against soft targets (half tracks). One caveat is that if the bore diameter of your gun is over 105mm, HE can be used against more hardened targets.

Shrapnel

This is a Soviet only shell and can be likened to a hybrid of an APHE shell and a pure HE shell. Low to moderate penetration with medium explosive power.

Armor Piercing Composite Rigid (APCR)

This shell type was designed to give less effective guns more punch against newer and more armored targets. The shell is comprised of a very dense sub-caliber projectile surrounded by a softer casing. This allows the shel to be lighter and have a much higher muzzle velocity. The small and dense (typically tungsten carbine) sub caliber shell will penetrate more armor than an APHE shell from the same gun. The damage after-effect is similar to plain AP but penetrates more. In smaller calibers, the APCR shell will have much improved penetration at short ranges but lose velocity and penetration at medium and long ranges (when compared to AP).

Armor Piercing Discarding Sabot (APDS)

This works very similarly to APCR in damage and penetration. The difference is that the sub caliber shell is surrounded by a light weight sabot. When the shell leaves the barrel, the sabot is removed from the penetrator due to wind resistance.

High Explosive Anti Tank (HEAT)

This is a technology that was put into practice during WWII. HEAT warheads are shaped charges and don't penetrate their target using kinetic energy (like all other AP shells). The HEAT warhead is hollow and contains a copper cone/funnel. Behind the cone sits some HE. The fuse is on the nose and when the shell impacts a target, the HE detonates. This detonation behind the thin copper cone causes it to collapse on itself producing a high velocity copper slug. This slug is projected (at very high velocities) towards the armor its trying to defeat. HEAT is good because it's penetration is not dependent on muzzle velocity. This makes shorter barrel guns more effective. HEAT can be defeated by spaced armor but when it penetrates, it does so similarly to an APCR shell but with a very high chance of setting components on fire.

Remember:

more penetration doesn't always mean better ammo.
AP is like a big steel bullet. Goes through stuff and that's basically it. It might throw up some armor fragments that damage stuff along the way. Variants include APC (capped) which is better against sloped armor, APCBC (capped, ballistic cap) which has a cone on the front to make it more aerodynamic, meaning the shell holds its speed and penetration better at long range.
APHE is the same as above, but it has explosive filler, meaning it explodes after penetration, for some nice fragmentation damage. Note that some rounds don't have HE in the name, but have explosive filler (Germany does this, for instance). So see if it does or not, just look at the icon of the shell. Grey "splash" means solid shot, yellow "bang" means explosive filler.
Shrapnel is the same principle, but it trades penetration for some extra fragmentation damage. Some tanks like T-28 have Shrapnel as the default ammo, use it until you get APHE.
For most tanks, HE is largely useless. Only intended for targets that are thinly armored or open-topped, like armored cars. However, for very large guns (122mm and above) HE is great, because you can simply shoot the turret of enemies and the fragments are so powerful that they go through the top of the hull and wreck $hit.
HEAT works basically like this: when it hits the target it explodes, launching a stream of metal into the enemy tank. It's mostly for short barreled guns like on the early Pz IVs, simply because their AP ammo is crap (low velocity on the gun). Some top-tier tanks use it too (M103, SU-122-54). Does not lose penetration over range, and is countered by spaced armor.
Now APCR/APDS. It's basically a solid penetrator, like a spear that goes through the tank; it does not explode inside targets. It has better penetration than standard AP, and is quite powerful in some situations. The German 50mm and 75mm, with their poor explosive damage on the normal AP, can use APCR to great effect, because you can hit a crew member, and the round will keep going and kill the guy behind him. Against some tanks, you can kill 3 crew with one shot in this manner. T-54s can use this to laugh in the face of the Maus' turret front.
Try to carry around 30-40% total ammo. This leaves certain ammo racks empty in the tank, reducing the chance of an instant kill.

[SticcestBoi]

Great Job

[Axius]

@SirCaptainDavid

Actually, that's not really biased. The Maus was planned to be 200 tons, with the thickest armor of any tank of that era (maybe even today too). The armor would've absorbed almost all damage. The main exception would be bombs from aircraft, and repeated AP rounds.

[HeavyDutyDerby]

T-54: Hey Maus!
Maus:???
T-54:"Shoots Maus"
Maus: Damn
T-54:Ha ha ha ha
Maus: (Nothing happened) ROOOOAR!!
T-54:What? It did nothing? Gaijin!!!!
(German Bias =) )

[Moth]

Thank you for your guide! That must have taken atleast 5 hours to make up! This has helped on my knowledge for this game and will help me in the future! Very Impressed! Good Luck and all the Luck to you! :-)

[Khias]

Impressive guide. You have done your research.

[Lagonova]

Wow, very good guide, thanks for making it!

[dewby]

good tid bit of trivia knowledge here thanks!

[Sanya V. Litvyak]

nice

[agapchap]

No AC shell :(

[Containment Warlord]

concise, factual and informative. this is how guides should be done, I hope you will consider doing more guides as there aren't enough like this on steam.