Hello,
Some weapons ignore the effects of FArm (2HCC and Elephants in melee ; firearms and sometime crossbows/powerbows for shooting).
I guess this is because of the enormous energy and/or small area of application of the attack which means that wearing a full plate offers no benefit over a simple reinforced leather or small chainmail.
If so, I wonder how logical it is that these same circumstances lead to those weapons upgrading against Unprotected targets, where the upgrade compared to Protected stems from them being more vulnerable...
How is such a perforating attack more deadly to a naked Pict warrior than to a Viking huscarl ?
Best,
Antoine
EDIT : I removed references about artillery, which were irrelevant