OK, the shooter had and used a range finder. Why?
Did he not know the range from the roof to Trump? If it was a deep state setup, the range was known to about 1/2 inch.
If someone pre-dialed his gun, he did not need to range.
If he was a video game shooter, then ‘range finding’ is part of the shooter’s procedure, and he ‘should do that’.
If he had never been there before, and was really on his own, maybe range finding indicates that.
Like many have said, 223/5.56 is so flat that if he had any estimate of the distance he would not have to adjust/compensate (unless he watched some movies or video games and they did).
I am suggesting that his use of a range finder indicated his state of mind. ‘I am supposed to to this, for accuracy’. Maybe meaning he was not set up for the shot, thinking he was on his own.
But then, if he was on drugs or meds (did anyone check - has he been cremeated yet?) this was just a detail for him; the big picture was him shooting.
Yeah...the original M-16 A1 rear sight had a single aperture for ranges 0-300 yards(maybe meters). We’ll never know where he was aiming...center of mass, head shot...