So after starting up fo3 and playing awhile I wanted to see if I could kill fawkes so after preparing (i.e kill all in npcs in area but saving before hand) after that I started fighting fawkes I started with some mini nukes (18) that took off about 20% of his health and then started using a minigun which did very little so I switch to a Tesla cannon which took about 20% of his health and then switch to a blackhawk,victory rifle,Xunlong assault rifle etc till I finshed him off with the Blackhawk. Then I committed suicide and reloaded the save before the battle.