It's pretty simple to verify yardage after the shot. Go to the downed animal with your rangefinder and let you buddy shoot it back to your stand! Sure makes for a pretty good witness, at least in my case it did. Particularly when we had two FWC guys with us. Of course, you have to range the animal BEFORE you take the shot, too. My bet is some of the shots mentioned in this thread describe estimated yardage, but who can be be sure? This is all about the comfort zone. Practiced, confident, and deadly.
BTW, the .308 is capable of 400 yard kills but you have to know your load. It's all about retained velocity. A 165 NAB at 2850 drops about 19.25 inches at 400 yards with a 225 yard zero. Retained energy is ~1620 ft/lbs. If the shot jumps to 425 yards you have another ~4.5 inches of drop, and energy goes to ~1550, which is enough to ensure a clean kill. You just have to understand what happens to your bullet WAY out there, and you have to know your yardage. You also have to practice. That extra 4.5 inches could cause a clean miss, or worse, you could mortally wound a magnificent animal and never recover him. Plus, a 10 mph crosswind could move your shot over a foot depending on the angle, not to mention the hillside factor. Interesting puzzle, huh? 400 and short change for me, with ideal conditions, or I will CONTINUE to pass on the shot. Drummer