I do not know what I should consider a mature deer here. Never had one aged. Going by rack size only, I would say I have killed 2 bucks over 5 yrs old. Taxi told me that one was maybe 7 and the other one 5 1/2. I have taken several bucks in the 2 -3.5 year range I suppose, but not for sure. I can't really say that Im successful, Maybe a mature deer in Va is 5 or 6 yrs old. In that case Ive only killed 2, so I wouldn't consider that successful after 20 yrs of hunting. My 2 cents!!