Truthfully no one who plans 800 yd and longer shots on game is using an off the shelf rifle. There are many custom rifle makers that deliver rifles capable of those feats and most are in the $3.5K - $5K range. And that would be minus the glass, which at a minimum for a serious long range hunter will be in the $2K range. What I’m saying is someone who is hell bent on pursuing game at those ranges has worked their way up over years in the field and bench as a rifleman to understand what it takes in skill and commitment. The money spent at those levels is based on a serious commitment that has taken many years of deliberation to develop. From your own account your friend sounds like a dreamer who has read to many magazine articles. My advice with his new off the shelf purchase is to get closer to the game and see how proficient they are at 300 yds with a 20 mph crosswind. My guess is this person will become very uncomfortable shooting at that range under those conditions let alone doping wind at three times that distance.