A combination of poverty and culture . <| sep |> No , it ' s more like we have a whole bunch of evidence to show spells working one way , nothing to show the oppositeIt appears to my uninitiated self you ' re making a jump up without good evidence . It ' s like saying I can punch through a piece of paper so I can punch through a sheet of metal . There is an appreciable difference between people getting hit with it who are wearing shirts and pants vs someone who is wearing head to toe armor . plus we have the whole thing that they did used to wear armour and use swords That and the killing curse is old enough and was notably used somewhat commonly in what would ' ve been towards the end of the period . Again , did they use it on people wearing armor ? Just because it was used in that era doesn ' t mean it was used on people who were wearing armor . You ' re making a leap that although reasonable is not definitive as far as I can tell . Really , the biggest problem with arguing against is trying to find evidence spells react differently to metal armour then to cloth armour , Again metal armor , especially head to toe , seems like a higher standard than just cloth . So rather than trying to find different reactions could we start with people actually using it on armored individuals ?