Had he actually shot one of them, and evidence shows that he shot that person at an angle that indicates that person wasn't a threat, the book would have been thrown at him... And it's pretty damn easy to tell where a bullet goes in and comes out to tell it's direction.
I'm not a gun expert but I know you'd get some hard stares or worse if you shot someone at a bad angle, like 180 deg. into the back. My point was that it shouldn't matter if he hit them in self defence. That's the kind of gun owners we need. What's a shot across the bow if you don't hit one from time to time?