Well his first 2 losses were by decision to McCallum and Kambalay, I don't think you can blame only his chin... And as for the Jackson fight, there is noone in history who would not have been KOed at that weight from that punch imo (except Hagler)... Wouldn't be surprised if it dented his chin considerably... How did he lose to Frank Grant by TKO, was it a one punch type thing again?