Ich hab es gerade noch einmal geschaut und so steht die Regel im Regelbuch zu breaching
When rolling To Wound for a model that has the
Breaching (X) special rule, or is attacking with a weapon
that has the Breaching (X) special rule, for each To Wound
roll equal to or higher than the value listed in brackets,
the controlling player must resolve these wounds at AP 2
instead of the weapon’s normal AP value. This rule has no
effect on models that do not have Wounds, such as models
with the Vehicle Unit Type.
Also wird die Regel betroffen durch die Salamanders Legionsregel