He did not have on a protective vest. think about what you are saying, if you have never been a sniper, then you have no idea about why or what actually happened. The shooter was above Kirk, he was at an elevated position and since they are in Utah, a mountainous area, I do not know what the linear or geological declination was from the end of the barrel to the point of impact. If you are shooting from an elevated platform and your target is below you, at a distance of 200 yards, then, the trajectory of the path of the bullet is downward, plus, wind value, plus, elevation, plus declination. he didnt have on a vest. if you have never worn a bullet proof vest then, then how can you put on here that he may have been wearing on. I wore one for over 37 years. He did NOT have on a vest. that what you described is the impact of the bullet and transfer of energy downward as that is the path the bullet trajectory. the outline of his shirt decal is most likely what you are seeing. The bullet struck him in the neck on the left side, severed the corotid artery, probably also severed the top of the aortic arch and most likely exited his body in or around the Latisimus Dorsi muscle. thus the reason for such rapid blood loss and his posturing arms at the time and point of impact from the projectile.
He was dead within a fraction of a second of when the bullet made impact with his neck.
His brain got scrambled at the point the hydrostatic shock and hydrolic effect of the impact blew out the Circle of Willis and his brain stem was detached upon point of impact.
A 30-06 150 grain projectile is hugely significant in both velocity and foot pounds of energy, if that is in fact what this turd used. Betting it was 180 grain or above.
A lot of folks like to speculate but you have never been in these situations, never been trained and never been shot at. Please dont speculate. Because, you flat out have no clue what you are looking at.