RE: 40 yard shot
When I bought my new bow, one of my goals was to increase my maximum effective range to 40 yards. I worked hard all spring and summer, often practicing out to 70 yards. My groups were acceptable for hunting at all my practice distances. When I tuned my broadhead tipped arrows, I had nice tight groups at 40 yards and was very confident of my ability at that range and felt I would take a shot at that distance if conditions wer absolutely perfect.
I saw plenty of deer at 40 yards and sometimes conditions were perfect. I never took the shot. The longest shot this year was 32 yards and the deer started walking just as I was pulling the trigger. I could've and should've held off, but didn't and was lucky enough to recover her.
A 40 yard shot is marginal because of what can happen--no matter how good you are at that range.