Emma Ness’s Reviews > Snape: The definitive analysis of Hogwarts's mysterious potions master > Status Update

“They can both cast [Expelliarmus] equally, using each other’s wands interchangeably, because Harry’s magic and Draco’s magic are compatible.” Not true??? There’s a chapter of HP 7 where Rowling explains wand lore. The reason Harry and Draco can use each other’s wands is because they disarmed each other. The allegiances of the wands changed, it has nothing to do with their magic being “compatible.”