Patience is the name of the game. 40 yard shots in the woods are iffy. If you were sure it was 40 yards exactly and you practice that shot alot, then maybe it' s ok to try. But at 40 yards your arrow is dropping rapidly. Any error in your estimated distance results in a wounded or missed deer. Your odds to take the deer are much greater when you wait for the deer to get closer. anyway, keep practicing and hunting and good luck to you.