best way to kill him is get a pistol or scavenger and make him go to the water but watch out the more damage he take the faster he runShoot him a lot, with powerful guns, preferably upgraded. The Ray Gun, LMGs, Death Machine, Scavenger, upgraded LAW, Shotguns(?), Dragunov(Not very well though), and any other gun you can think of that puts out a lot of damage.by using a pack a punched gun, preferably the Scavenger. If you use the pack-a-punched VR-11 on george, he will only dissapear for a couple of minutes. you can tell if he is close to dying when he starts to glow orange-yellow. if you get him in the starting area lake, you can repeatedly shoot him with a pack-a-punched Scavenger, and he will eventually die.
MYTH - it is suggested not to shoot him while he is beginning to get angry AKA when he jumps up and smashes his hammer.