My "best" is 378 yards offhand on a running coyote with the .22-250. I've drilled multiple mulies with the .243 between 375 and 450 and got my antelope at 573 with the .270WSM. I've tried much longer shots on coyotes and missed but have always been able to get closer than 500 to deer and elk without them spooking.

John - what caliber was that on the 1017 yard shot?