With the right rifle, range finder, rest, weather and an animal that was cooperating perfectly about 600 yards would be as far as I go, and only then if I knew I could not get closer. I shoot a 7 Mag, it peters out pretty darn fast past 500, and too much can go wrong too fast beyond 400. It would have to be PERFECT conditions.
In some situations I have declined 40 yard shots, and in others taken some 450+ yard shots. The situation at hand is critical to ranges possible. I have shot an elk at a stepped 470 yards (+ or - 40 yards probably) prone, it was feeding and unaware of me and there was nearly no wind on a flat shot. I took nearly 5 minutes setting up and preparing to pull the trigger as there was no way to get closer. I drilled it well, and it ran about 30 yards before stopping, weaving and toppling over. Earlier that day I let one run off after busting it out at about 25 yards, I just did not have an angle. Uphill, downhill, wind, rain or snow, movement, range, rifle, optics, ammo, lighting, escape routes of wounded animals, and countless other things need to be considered before a long shot is taken on a game animal.
My max range can be measured in feet all the way through several hundred yards.