688 yards is a stunt- not hunting. Has anyone ever hit a deer or elk that showed no sign of being hit? Would he hike near a half mile to check. ever try to hit an animal after it begins running 'raggedly' with a busted leg? What if you break the jaw and it starves to death?
IMO that shot is irrsponsible. Game animals are to valued and not 'sniped' to prove you can.