I'm going out on a limb here, but I will suggest that John Kingsley-Heath recommended the.243 because most of his clients could better put a .243 bullet in the right place than could be done with a hard-kicking magnum.
Likely, but also a lesson on what is enough for the task. Don't forget that the tradition built around a 7x57 is based on being enough for the task and its shootability. Same with a .243 or .270 as recommended by Aagaard, whether its trendy on here to like one or not.
"Enough for the task" is never an interesting topic compared to the ever mythical "best for the task" after all, what else would we talk about around the campfire?
