Nervous jurors asked a judge to have a murder weapon checked when it was presented at the David Bain retrial in the High Court in Christchurch.
The .22 rifle is the one the Crown says he used to kill his family on 20 June 1994. It was being introduced as an exhibit on Wednesday.
But the jury was nervous about its presence, along with live ammunition which was also an exhibit.
The jury foreman asked the judge to ensure the rifle did not contain any live ammunition and a police officer was asked to check the weapon. It was empty.
The trial continues.
The Crown says Mr Bain, 36, murdered his parents Robin and Margaret and siblings Arawa, Laniet and Stephen at the family home in Every Street, Dunedin.
The defence contends Robin Bain killed them before shooting himself.