If you mean turning off the collision box totally, it will not work. Because no collision box means the shell cannot hit anything, whether friend or foe.
You should look for changing "force condition" instead. It is under mod settings of parent mod "Schall Tank Platoon".
The parent mod already provided the choice to change those ammo categories involved.
For example, the entry "Force condition Cannon shells", the vanilla (unchanged) default is "All". Changing it to either "Not same" or "Not friend" will make them not colliding with your own entities, like firing over walls or buildings, yet still hitting the enemies.
