Has to be, the guy wouldn’t even be in the scope when he pulled the trigger. We are talking dealing with cross winds, elevation, image distortment, gravity and even at that distance earth curvature all while battling diminishing power as the bullet loses steam. This sniper literally made a shot that will be almost impossible to beat.
In some sniper movie with Mark Wahlburg as the patsy, they had snipers advising them. In an interview one of the advisers was saying how they couldn’t show in the movie what really happens. (In the movie the guy gets shot in the head and some blood flies out the back.)
The adviser said “At those ranges the bullet is going down more than across - it would enter the head but then angle down - the head would be gone, and a big slice going down the torso.” I have no way of knowing whether the guy was telling the truth or not.
I do recall the time I thought I could kill a rabbit with my .308 and still have some food. I figured a “head shot”. The round entered the head - but blew out half the body as it angled through. Learned never to try that again (I was only about 16 - stupid kid!).
Luck definitely played a role. He might make that shot once in a hundred tries, but most of us won’t pull it off once in 10,000 tries. Think of the 2-D gaussian scatter pattern. He must have low bias and low scatter.