Bobblehead - Big Guns

 is one of a total of twenty Vault Boy Bobbleheads found throughout Fallout 3. It permanently improves your character's Big Guns skill by 10, to a maximum of 100. The inscription on its base reads "The best way to win an argument is to be the loudest".

Location
In the basement of Fort Constantine's CO Quarters.
 * http://www.youtube.com/watch?v=1IcgHfX2Wlo