Things a guy should always keep in mind if preparing to take a shot at those 1000 yrd ranges at an animal, all that animal has to do is take a step at the same time you break the shot, if shooting for behind the front shoulder or the shoulder you just hit that animal in the guts or hind end,
Not to mention the slew of other variables.
Hitting a target at 1000 yards on a surveyed range with wind flags is one thing, but generally not beyond the capabilities of most shooters with a little instruction and practice.
Hitting a game animal is completely different, because the range will be variable. If your range call is off by 25 yards, your elevation will be off by a foot even with an excellent LR round, the 338 Lapua. As I mentioned above, getting the wind call slightly wrong at that range will put you off a foot or more.
Hunting you don't get wind flags. You don't have a data book with your sight settings from the last time you were there. You don't get sighters. You don't generally get a coach.
Shooting at game at those ranges is unethical.