2. Never point a loaded firearm at anything you're not willing to shoot.
3. Always be sure of your target and what's beyond it.
4. Keep your finger off the trigger until you're ready to shoot.
Our little marksman evidently violated not just one, but two of the Cardinal Rules of Gunhandling, and a little boy is now dead because of his stupidity
Throw the book at him. Then pick it up and throw it at him again.
We were talking about this at work, and everybody agreed - this was a tragic incident that was entirely preventable. Moron Number One was being stupid, evidently failing to realize that a 2x4 is most definitely NOT a "safe, secure backstop."
I've put arrows through 2x4s. A .22 bullet, travelling at much higher speeds, with much greater sectional density, will go through it like it's not even there.
Throw the book at him.