Long range shooting isn't usually a speed event.
So, what would the reason for needing a semi auto?
Unless it's for more of a general use, with other possibilities, my choice would be clearly for bolt action.
And with practice, they can be quite speedy.
Not all that much slower in .308, considering recoil recovery time.
Walt Kelly, alias Pogo, sez:
“Don't take life so serious, son, it ain't nohow permanent.”