in a post like this you will allways get the neysayers who say its not ethical. Most of them are guys who just wont put the time in to practice to become good shots to begin with. I shoot probably a dozen deer a year at those ranges and it with a good gun and a good trigger man behind it its very doable. In my opinion though when the range gets out past 350 its time for a mag rifle. Not so much for the trajectory as even your 308 will hit deer out there if you know your gun and know your loads trajectory but the mags will just put down deer better at extended ranges. I like something like a 257 wby, 264mag, 7mag or a 300 mag for doing it. If its your land or you can get permission before season put out some targets at various ranges and see EXACTLY where your gun and load it hitting.