Personal experience answers this question the best.
Take a brown paper bag from the grocery store. Open it up and place it on it's side in the forest in a suitable spot. Now pace off a suitable distance and have at it. No marks, or aiming references, just the imaginary kill zone, right behind the shoulder. NO misses allowed!! Twenty five yards takes on a whole new meaning. An effective range can be determined without any doubt at all!
It's close enough to the size and color of a deer, and you will find that different lighting conditions really matter.
Anyone in the past had the same problems that we have now. Probably more. I agree with Flintlock, 25 yards, give or take. But I would sure rather take a few yards myself.
I shoot 67 # @ 28" and oh yeah, heavy and fast! But unless I can "pick that spot" I'll get a fast miss. Much beyond 20 yards, there ain't no spot, just a brown fat deer in a winter coat, probably in deep shadow.
Wern't any different for any hunter anywhere in the world, at any time in history. Just some of them could shoot better'n me. Woodbutcher