Nice buck, but I hate to say his teeth show him to be only 2.5 years old, maybe 3.5 if I could get the teeth in my hands and look at them. Certainly no older. That buck would have been a monster at maturity.
There are lots of websites that can show you how to age him based on tooth wear, and your pics are good enough to do it with.
Try this one
http://www.kerrlake.com/deer/teeth.html