The tank is a pre-War combat vehicle which has been heavily modified over the years. Unlike other Fallout Tactics vehicles it possesses a weapon, a tank gun, which deals 50 to 120 damage with a range of 50. There is a Brotherhood of Steel insignia on its side.
It appears the pilot'sBig Guns skill is used for accuracy and damage calculations with the tank gun, not the gunner's. In reality, it is still the gunner's Big Guns skill used in the calculation for the tank cannon, not the driver's. Due to coding problems between the tank turret and tank vehicle, the message reports that pilot label, not the actual shooter.