I have never shot at any animal over 500 yds away in my 70+ years of hunting big game. I killed an antelope at 496 yards away about 10 years ago.
I shoot mu own handloads and I have a Leupold Ballistic Turret to match my load. It is calibrated to 900 yards. I have one on my 25-06 and 300 Wby. When I first got them and set them up, I set up targets at 500, 600 and 700 yards. I got sub moa groups of about 1/2 minute on both rifles. That's the last time I shot at over 500 yards. Unless I have near perfect conditions ( light, wind, a great rest and not have tired eyes), I keep my shooting at 400 yds or less. I also use a Sworo bino/range finder combo.