Down here, unless you are hunting powerline/pipeline right-of-ways, Whitetail hunting is not normally a 400 yard sport, and as my friend DD said I can barely see that far anymore!!
Personally, I would not take that long of a shot! IF, you practice a lot at that range and conditions are PERFECT, then go for it!
As for making the "hail Mary" shots, that is a peeve of mine! I respect the animal and the sport too much for that!
A "no shot" is a "NO SHOT" even if its a lifetime buck!
You hear it all the time,"I wouldn't normally have tried a shot like that, but it was so big, I had to try!" BS!