My longest shot on a deer was at 35 yards. Was shooting a very fast compound with carbons at the time. Between the point of no return on the release and the time the arrowgot to the deer, the deer took a step on me. Turned a double lung into a single lung/liver shot. We let the deer go overnight and found it in the morning. But I vowed not to shoot at that range again.
I keep my shots within 20 yards now. But depending on the circumstance may shoot to 25.
The quote below contain some info on how much a deer can move before an arrow gets to it. Below that is an average grouping for me at 25 yards.
A bow shooting at 280 FPS a deer moving at 2 MPH:
At 35 yards a deer can move a little over one foot by the time you shoot and the arrow gets there.
At 12 yards a deer can move a little over four inches.
Remember I am calculating this based on constant speed (deer and arrow), of course the arrow will slow down a lot by the time it gets 35 yards. So the 1 foot measure will be greater.
If you need the calculations let me know.