I wish the 6.5-06 was a factory round, w/26" bbl and a 140g amax, it would be bad...
My record is 775 yards w/300 RUM and 200g SMK at 3200fps..Shot right over his back the 1st shot, the 2nd shot rang true..I dont consider it luck..I shoot quite a bit out to 800 yards and with a rangefinder, good MOA or less rifle/load, and little to no wind, it can be done quite regularly. Especially if you've got a full blown custom rifle, 800 yards can be pretty easy with good conditions...My rifle was a rem 700 LSS w/6-18 Leupold target scope. I used a harris bipod laying prone to make the shot. I spotted the coyote sitting over on a hillside across the canyon and ranged it, clicked it, and dumped it. There was no wind that I could tell..The rifle shot enough 4-8" groups at 800 yards so it was more then up to the task, the shooter and condidtions is all thats left..
I can see coyotes from 10 yards to over a mile where I hunt them. Sometimes they dont always come in, they just sit on a ridge top and outwit you. Its either dont shoot, or practice enough at long range to become proficient...
What you need is a relatively fast, not a barrel burner, somethign that shoots 2850-3000fps with a good high BC bullet usually around .450 and up is great, that will buck the wind a little more for you, and retain more velocity/energy as well.
Oh yah, did I mention you have to practice?? Not only do you need the time, you also need the place, which is the most important part..