Ran into that when my brother filled his pronghorn tag a year ago. We just glassed till dark and had a good idea where the buck was bedded. Then I dropped him off and he walked into the little hump (I’d call it a knoll, but it was only 2 feet higher than the rest of the area) laid down his pack to hide behind and waited for light.
It is definitely Dooable at 650 yards with the good equipment @1wildcatfan has and the Luck to get one in Position.
Heres an Antelope my friend in Oklahoma got a while back. 1,220 yards. I saw the video.