"An offender was holding a little baby hostage and his intentions were pretty apparent."
After trying to gain access to the house, the gunman fired a shot "that went over my head", Mr Perry said. "I was in a crouch position."
They withdrew from the house, and Mr Perry later fired his rifle into the gunman's shoulder, forcing him to drop his shotgun.
He then stormed the house and, after a desperate hand-to-hand struggle, disarmed him.
"He [the wounded gunman] grabbed the shotgun and jammed it into my throat and tried to pull the trigger," Mr Perry said.
"I had a feeling of tranquillity - which I didn't use in my report because I couldn't spell it," he said.
The Detective Inspector was struck in the face with the gun during the tussle and cut. He was later awarded a George Medal for his part in arresting the Whangarei gunman.
The earliest days were "rather akin to Dad's Army", Mr Perry said, but the AOS very quickly became an advanced force and a valuable police asset.
"It was a learning process, we gained experience from each operation. We were pretty efficient. Commensurate with the situations we were contending with in those days, we were matching up," he said.
"We worked as a team. It was a great team and a pleasure to belong to and an honour to serve."