I always get in trouble on these threads because I have, IRL, met a lot of people who claim to be long range experts, but turn out to be FOS. In fact, that defines pretty much all of long range experts I have met. So while I have no doubt, at least intellectually, that the person capable of 500+ yard first shot hits exists, I have never met him, and my personal experience indicates that odds are anyone who claims to be that guy is a first class liar.
Essentially, the folks I have met who claim to be capable of long range hunting are, in actuality, capable of sometimes being able to hit long range targets from a bench rest, at known distances, after a few ranging shots. When we add a touch of reality to the exercise -- unknown range, a bit of wind, a hastily assumed field position, first shot from a cold clean barrel, poorly defined aiming point, and a bit of buck fever -- something like a 50% first shot hit percentage beyond 300 yards is being generous. And few things in this world make me as angry as three-legged deer.
So forgive me or not, but I have a serious bone to pick with people who casually talk about 500, 600, 800+ yard shots.
In the real world, 200 yards is a pretty fair chop and 300 is a reasonable limit for almost everyone. Unless you are a very special rifleman with a very special rifle, these 500+ yard shots are not something to be attempted, let alone bragged about.
<edit> Ranting aside, I am a hunter, not a sniper. My game is to see how close I can get, not how far away. I would be embarrassed to admit that I could not get within reasonable range of my animal, and frankly, if I cannot do it, I do not feel I deserve him. Three hundred yards is my absolute limit with a scoped rifle, under ideal circumstances, because I need to be 99% positive of a first round killing hit. Anything less than ideal and my distance shrinks. I am not comfortable, generally speaking, until I am within 200 yards, and would prefer 100 or less.