That depends on the totality of the circumstances. If having the gun pointed at the intruders was legitimate, then just because the actor did not intend to pull the trigger it doesn't turn a legitimate action into manslaughter.
I can easily see the AD occurring when, depending on whose version one believes, the punk lunged at Mr. White, or tried to slap the gun away.
If a punk lunged at him and he fired in self defense, why the hell would he then claim he didn’t intend to fire the firearm? Either he did it intentionally as an act of self defense, or it was an accident and he is negligent. THere’s no in between.