I pretty much subscribe to the idea of whatever distance I can shoot 4" groups, that is my absolute maximum. As some others have siad, with wind, edgy animals, adrenaline, and other factors possible group size in hunting situations is likely to double---or more. That being said, I often shoot 2" groups at 40 yards with sub-4" groups the norm. I set my maximum in the woods at 30 yards. There are enough things to go wrong without me adding poor judgement to the equation.

One thing I would say though. Practicing at even longer distances out to 70 yards sure does help with the concentration, making shorter shots seem easier.