My advice is this: Speed kills- EVERYTHING! It will kill barrel life and accuracy. There will be some here that will say it is obtainable but it will come with a price. I would suggest the 6mm Rem AI or the 6.5 -284 or maybe a 6mm- 284. A 1-8 for the 6mm and maybe a 1-10 for the 6.5 if all he will shoot is 100-120 gr.