A 40 yard shot is only acceptable to those who have an effective yardage of 40 yards. There are those that can make it without hesitation. I've taken two deer beyond 40 yards without incident. One was a 42 yard double lung and the other was a 41 yard double lung. I've never missed an animal beyond 40 yards seeing they were the only two attempts beyond 40 however I have missed animals well under 30 yards. The noise factor is a variable regardless of 20 yards or 40 yards, the animal will react one way or another or not at all depending and regardless. Wind factor only come into play on just that..windy days and elevation is less a fact at 40 yards than it is at 20 or under because of shot angle.

The only people that should take a 40 yard shot are those who has 40 yards in thier effective range and when the shot presentation is correct. There are those who should never attempt a shot beyond 30 yards and some less because of their own personal effective range.

The most important factor is to abide by your effective range and never push the envelope, for some that's 20 yards, for others it may be 40....you and only you can make that decision.