I think Paul Kearsey found the closest thing to a "one-shot stop bullet" in the movie Death Wish 3... The Wildey .475
When asked is that a .44 Magnum, he replied - "No, .44 magnum is a pistols cartridge, this is a shortened version of the
African Big Game cartridge".
Can't imagine anyone - even the mythical 350 pound druggie wanting to continue the fight (if able) after being hit by one of those!