Play the level No One Gets Left Behind and make sure you pick up the C4 before you meet up with the rest of your squad. Next you'll enter the Prison Camp area and there are tons of fences, houses, walls and other stuff to blow up but the real nice thing is the many ammo boxes. Kill the guys in one area and you're free to plant C4, explode things and then repeat until all is gone. Move to the next area and repeat until nothing stands.