Sad if true, we shouldn't 'celebrate' death even its the enemy but I'm calling bull anyways. At that distance(+8,800 feet!) there's no way a bullet, even a very large caliber one, would travel in a straight line like a freaking laser as the video leads us to beleive - Gravity and air resistance would drag it down. You'd have to compensate for that by aiming the reticle above the target not directly on it!
You are partially correct. But the caliber used was more than 50 and who knows what was the scope used.
Beyond 100 metres the bullet begins to drop along its trajectory as gravity’s pull starts having a greater effect. The shooter then has to aim above the target in order to hit it. That distance between the target and the shooter’s aim is called elevation. The further from your target, the greater the elevation. Keith Cunningham, a marksmanship instructor in Minden, Ont., and former sniper for the U.S. and Canadian militaries, calculated that the elevation required to hit a target 3,540 metres away with a .50-calibre rifle would be 137 metres. “So pick a spot 137 metres above your target and aim at that,” he says. “That’s way up in the sky some place.”
Luckily, adjusting for elevation is somewhat automated, using what’s called the elevation knob on the rifle. This lets the shooter look straight at the target and still have the bullet fire above that. That said, Cunningham says he’s never heard of a rifle that can account for 137 metres of elevation. He estimates the shooter would have had to holdover—a term for aiming above the target—by about 70 metres on top of adjusting for elevation on the rifle