Shell Normalization

1. Definition
2. Why is this important?
3. Example:
4. What doesn’t shell normalization work on?

Definition

Shell normalization is how much the shell “takes away” from the angling of enemy armour. The enemy armour MUST be angled for shell normalization to affect it.

AP has 5 degrees of shell normalization
APCR has 2 degrees of shell normalization
HEAT and HE do not normalize.

Why is this important?

Shell normalization effectively worsens the enemy tank’s angled armour. This is why when you look at tank’s armour in game, it may appear different to the armour values that were shown by armour viewing websites.

Example:

Above is a comparison of the Chinese tier 10 heavy tank 113, facing against 276mm of penetration, look at the upper plate to see differences of normalization.
The very left image is AP with 5 degrees normalization, the middle image is APCR with 2 degrees normalization, the right image is HEAT with no normalization

Armour viewers such as Blitzhangar or Gamemodels3d will tell you the upper plate’s thickness with no normalization, which is what HEAT sees. 
(Note that WoT’s 113 has less armour than the Blitz version of 113, don’t take these armour images as showing what kind of armour the 113 has, its only here to show what difference shell normalization makes.)

(Note that this is from tanks.gg, a website for WoT. There is no such live armour viewer for Blitz, at least not for free.
The HEAT in the right image is 275mm, as there is no shell with 276mm HEAT penetration in WoT, and 1mm penetration makes no difference at all.)

What doesn’t shell normalization work on?

Flat armour:
For example, the Excelsior’s flat turret face, shown as 120mm thick on Blitzhangar, is 120mm thick when enemies shoot at it in game.
However, if the armour is angled, then shell normalization makes a big difference, as shown above.

Auto-ricochet plates:
Armour plates with more than a 70 degree angling, will not be affected by the normalization mechanic. However, as soon as the armour plate becomes less than 70 degrees, normalization will work against it.

Armour with more nominal thickness than your penetration:
In the example shown below, the Tortoise’s armour plate next to the gun is 422mm thick (with enhanced armour on). The Obj.268 shoots it with 418mm HEAT, the shot penetrated 5/10 times (this was tested).
The Ho-Ri shoots it with 399mm AP, the shot penetrated 0/10 times (this was also tested).