And... when did President Bush do this? Are your referring to the AWB which expired last week? The Congress did not author, nor pass a bill to extend the AWB for President Bush's signature. I'm certain W had an interest in this bill not being put on his desk. Regardless, I do not understand what you mean by "Bush reversed..."
I am talking about what is admittedly a largely symbolic gesture, but important nonetheless.
When Clinton was in office, it was the official position of his Justice Dept that the Second Amendment refers to a collective right, which fit with their anti-gun positions. When Bush took office, Ashcroft reversed this by saying that the Bush Justice Dept regards the Second Amendment as protecting an individual right, as was clearly the Original Intent.
Now clearly the council of kings known as the Sup Court could someday rule otherwise making the official position of the White House irrelevant, but it is nice to know that the President actually believes in the true meaning of the Sec Amendment.