The Crown says police ballistics evidence shows the bullet that killed road worker George Taiaroa likely came from a gun owned by murder-accused Quinton Winders.
The High Court heard a bullet fragment removed from Mr Taiaroa's head came from Winchester Cooee Model 39 .22 bolt action rifle.
The murder weapon was never found, but Winders owned a .22 Winchester, which he claims was stolen in 2009.
An Australian firearms expert ran a series of tests on comparable rifles and found the markings on the bullet fragment matched indentations on bullets fired from the test rifles.
Detective Senior Sergeant Edward Schey from New South Wales told the High Court when comparing grooves in bullet fragments from one test that there was "a massive amount of agreement on this. I have not seen agreement like this before".
Walter Murphy, a forensic ballistics investigator with the New South Wales police, outlined on Thursday how serial numbers stamped on Winchester Cooee Model 39 .22 rifles he examined had serial numbers close to those belonging to firearms owned by Winders.
In his opinion, they were factory stamped with the same tool.
Earlier in the trial at the High Court at Rotorua, the jury was played a videoed interview Detective Steven Dunn conducted with Winders on April 4, 2013.
During it, Winders talked of having two rifles which either he had misplaced or had been "pinched" from his gun safe after his key ring with a safe key attached went missing in a burglary.
He had initially thought he might have left them behind after shooting goats but when he went back couldn't find them.
Mr Schey said Winchester Cooee rifles were included in the list of possible manufacturers of the weapon that fired the fatal shot and confirmed to the Crown and again to assistant defence lawyer Ken Paterson that the fatal bullet was fired from a rifle cut with the same tool as rifles he'd examined and test fired.
Their serial numbers differed by only three to five numbers from a rifle registered as belonging to Winders.
At the close of Thursday's proceedings Justice Toogood told the jury it was now estimated he would not be summing up to them until September 8.
This meant the trial would be running into a fifth week, not the four as originally planned.