There's a lot of good information and advice in this thread. Shooting at anything out to 1000 yds. requires that the shooter enjoy shooting the gun, knows his/her cartridge, can read the wind, and practices until they feel it the wallet. Get out to the range and get comfortable with what you have, then practice against your buddies to get the feel for making decisions fast. I've wounded my share of critters, found some, lost the rest. I have never shot at anything over 500 yds. away. My longest shot was 350 yds. on a White Tail hauling oats across a prairie in Nebraska. It went down to a 139 grain interlock out of a 7 x 57 Mauser. Do Elk just stand there at 1000 yds. and wonder why the dust is flying around them, or do they wonder anything?
The last Elk I shot at was 35 yds. away in the deep black timber of Bear Gulch in Eagle County Colorado. It did not stand still and wait for a follow up shot.