Not delusional, but definitely not sane.
He, who went hunting lesser beings, is actually severely damaged and, according to his morality, therefore the one that is lesser.
Interesting detail is that he had more than one plastic surgery, so he actually does feel inferior.
In short: typicall right-winger issues. Run over by their own fantasies since mid 1940s.
The psychiatric view of psychopathy is that it is a neurological disorder, but that it is not an insanity. That might seem contradictory, but it is not when you consider that to be insane, a person must be judged to be irrational and/or cognitively impaired such that their actions are not based on a generally accepted view of reality.
Breivik is rational, not cognitively impaired and his actions were fully reasoned by him within the same generally accepted view of reality that most of us share.