I hope you don't take this the wrong way. New to rifle shooting and long range hunting used in the same sentence are like nails on a chalk board.
Tell your frind to do himself and the animals a favor and get a .308 win and learn the way most of your good long range shooters and hunters have. Burn out the 308 barrel and he will be on his way to answering his own questions and learning limits and what it takes to long range hunt in a responsible way.
Things at long range go wrong faster than they do up close and although magnums will help cut wind and flatten out the ride, I always get new shooters out dialing a 308 and getting plenty to trigger time. When they are comfortable with the 308 and doing thing for themself and at the practical limit they will be ready for a 300 or 7mm mag to extend their shooting to the next level
