http://www.youtube.com/watch?v=ssl6tVKkUk0

The first 10 minutes of this video pretty much sums it all up.

I shoot 9mm, 5.56mm (.223) and 7.62mm (.308) in real life and I can tell you all three would go straight through that tin shed and out the other side (at the range shown), albeit with reductions in velocity and deflections at funny angles.

I'm not saying 9mm penetration should be lethal, just that it should penetrate and cause injuries.

5.56mm and 7.62mm on the other hand (again, at the range shown)would very much be lethal with center of body-mass hits (neglecting armour).

The current system is unrealistic and unbalanced. Why run to a stone house for cover when I can hide in this tin shed and be bullet proof? There is a difference between concealment and cover.