Big Guns is a Fallout, Fallout 2, Fallout 3, and Fallout Tactics skill. In Fallout: Brotherhood of Steel, Big Guns is not a skill but there are big guns in the game. It was going to appear as a weapon skill in Fallout: Brotherhood of Steel 2, the equivalent of skills in other Fallout games. Big Guns determines combat effectiveness with any weapon categorized as a "Big Gun," such as flamers, miniguns, missile launchers, Fat Man, etc.