17.4 Mortars and Artillery vs. Armored Vehicles
Onboard Mortars and off-board indirect fire (18.0) affect vehicles the same as small-arms fire; however, both OPEN AND BUTTONED armored vehicles compare their lowest armor factor and terrain TM plus 1d6 to the attacker’s FP plus 1d6. A vehicle with an unarmored facing is attacked as if it were unarmored.