I have a custom built 6mm Creedmoor weighs 19+ lbs and strictly bench gun it will comfortably ring steel to 1,000 yards, fun to shoot and easy to load for and in that heavy gun the recoil is like a 17HMR. it has 1 kill and that was a coyote at 647 yards.
For hunting big game I have a pair of CA mesa long range rifles in 6.5 PRC and 7mm PRC topped with nightforce NX8 - 2.5 - 20 x 50mm scopes, I have rung steel out to 1,400 yards with both of them. I also have a Remington 700 sendaro in 300 RUM pushing a 190gr LRAB at close to 3200 fps, I have had it out to 1,000 yards also very comfortably and have take a ton of game with it, I believe the longest shot on game was just over 350 yards. I know if I have time to get set up and range the animal do the dope and dial I could hit them well out beyond 600 yards but for me hunting situations are much different than ringing steel off a bench with a spotter.
Hitting a animal at 800 yards is not the thing really, it's where you hit them, the margin of error is small and a poorly hit animal makes for a very long day tracking, in my 50 or so years of hunting if I can't get close enough to an animal to make a nice clean ethical kill well I just pass. I have take 4 really nice antelope over the years and had many opportunities to take a shot at 600 yards but never really felt comfortable doping the constant gusting winds that are prevalent in good antelope country, in the end all were shot between 200 and 350 yards, lots of stalking and crawling but all were 1 and done.