There was no evidence provided at trial that Dunn was threatened except for his own testimony. In fact, just prior to Dunn's testimony, Judge Healey ruled that he would not give the jury the self defense instruction at that time. Which is why Dunn took the stand.
So you do admit there was evidence provided at the trial of Dunn's verbal threats and actions to act on that threat?
(Now couple that with bullet trajectories showing open door, testimony of people in car of Davis's escalation and aggressiveness, cursing at Mr. Dunn angrily, attempting to open door to carry out his threats on Mr. Dunn's life ALL of which back up the testimony by the esteemed Mr. Dunn)
So...what do you have to dispute this evidence?
You do understand correctly that verbal threats with the capability/ability to carry those threats to life or bodily harm are justification for deadly force, right? Self defense is to STOP the imminent commission of a forcible felony. When somebody says "I'm going to commit a forcible felony on you right now!" and makes an action to do so deadly force is justified. One need not wait for the forcible felony to occur, one is allowed to stop the imminent commission of one. Davis communicated, yelled, cursed and told Mr. Dunn he was going to kill him. You do know that killing or beating the shit out of somebody is a forcible felony, right?
Do you honestly believe Davis was not going to imminently commit a forcible felony on the victim Mr. Dunn? Because the evidence totally dismisses that.
Don't want to get shot? Don't threaten to kill somebody and then make a move like you intend to carry out that very real capable, credible and imminent threat.