Not those 2 specifically, but I've shot elk with a 30-06 which is close to the 308 and with a 300 WSM which is close to the 300 WM. After a dozen or so elk with the 300 WSM, I realized that there wasn't a single one of them that I couldn't have got just as easy with my 30-06 that weighs a pound less.

“In a time of deceit telling the truth is a revolutionary act.”
― George Orwell

It's not over when you lose. It's over when you quit.