Right now, because tank barrels can stick into things, and because the projectile spawn point is at the end of barrels that hang-over the end of the vehicle, there are a number for exploits one can perform. Stick your cannon barrel inside the model of your opponent to hit a different armor side, or keep from taking splash damage. stick your cannon through a building's wall to get at the gushies inside. hide behind an engi wall, stick your cannon through the wall to shoot at things on the other side remaining safe from pesky damage. I don't expect to see a solid fix for this, but it would be nice to shorten barrels, of move the projectile spawn farther back in the barrels or some such thing so it is atleast harder to exploit. A BE Heavy can stick his whole double barrels of goodness straight through any wall in the game if the tank is parallel to the wall.