I have some heavy skepticism that a shooter with a cold barrel and in hunting conditions can make 10/10 shots at those distances. I can make shot well beyond 600 yards on a bench rest and no time pressure.
Lets see them get 5 hours of sleep in a tent with 3 smelly dudes, hike 5 miles, glass the entire day. sit around in the cold for 9 hours, then make a shot all pent up and excited to see if they can make it.
I agree those shots are possible. I'm just not sure why you would take a shot like that when you can easily move in closer. People bow hunt these animals, its not like getting to 150 yards is impossible or even that difficult.