If your outside the rounds ballistic effectiveness then it may well be pot luck as when it is going through supersonic transitioning subsonic it is unstable until it sleeps again.
We have all seen WWII vet Ted Bundy (Dec RIP) with the think its an A5 .308 put 3 rounds into the head of the figure at 1000Yds being a 5" 3 shot group thats 1/2 MOA at that range which is pretty damn awesome.

I saw the burst on another sniper who took out a RH with a Barret S/A fifty aiming ** feet above his head think it was a 3 second flight time against a walking target the shot was at altitude so air resistance would be less he took the RH out with the follow up shot as he was aiming where the target was going to be.