At 1000 yards a 20x32" target is going to be very small indeed. If they don't have an indicator on it, or a spotting scope, they won't know if they hit it. The 600 yard standard high-power target is 6'x6' and they seem plenty small when actually shooting at them.
That 38x55 round is going to rainbow a good bit, he didn't appear to be compensating much for the bullet drop, even with the ladder peep site. Lacking other evidence of either calculated range, or target. I call shenanigans (especially with that amount of audible wind).
Ballistics chart attached. I don't think this was 1000 yard shot - maybe 1000ft (even that is granting a lot of benefit of the doubt).