This take place on Mission 6: Kasserine Pass.
This achievement/trophy can be a little difficult to attain, as some vehicle spawns are random. The best method is to play the level and complete the objectives until the Tiger Tank spawns. At that point, lay two explosives in the road, and head back towards the temple using the side path. As the Tiger Tank explodes, two vehicles should come driving out towards the temple, one is a transport truck and the other a small tank. At this point, take out the driver of the tank, then the gunner. The transport truck will stop and unload people on its own. Now, just get to a spot that you will be easily able to shoot both weakspots of both vehicles. Time your shots, and explode them quickly to get the achievement.
It is recommended that you "Save Game",just in case something goes wrong. Feel free to use explosives, or other methods as well.