Have you also run into problems taking out tanks in the PC game Jagged Alliance Crossfire. As in the other Jagged Alliance games, tanks are pretty tough to destroy.
The main solutions to knock out tanks are:
1.) LAW: Light Antitank Weapon aka Bazooka
2.) Rocket Launchers
3.) RPG short for Rocket Propelled Grenade.
4.) Explosives. Time delayed or remote controlled explosives.
5.) Grenades - Actually the Pineapple grenade can take out tanks if used in quantities.
6.) Rocket Rifle - It takes 4 shots to take out the tank on the military base with this weapon.Maybe you are struggeling with the tank at the military base.
You need to shoot the tank with 3 LAW shots on normal difficulty to destroy the tank.