Michael “Mike” Maguire, from Coomhola in Bantry, was killed after a stray machine gun bullet hit him in the head in a designated safe area.
A coroner has been told that the 21-year-old, had removed his helmet and armour before he was hit — although his comrades say this was normal.
The incident happened at the Castlemartin Ranges in Pembrokeshire, Wales, last May, during a training exercise involving members of the 1st Battalion, the Royal Irish Regiment.
His former comrades yesterday gave evidence at his inquest in Cardiff — which is expected to last up to three weeks.
Among them was Cpl Mark MacMahon, who had not been firing a weapon during the exercise as he was overlooking the safety of the men firing towards the targets.
While Cpl MacMahon gave details about his background and a previous training, when faced with questions about the day of the shooting he replied: “I regret I cannot answer that due to the ongoing investigations.”
Coroner Mary Hassall said that under rule 22 of the coroner’s rules any witnesses at an inquest could refuse to answer questions if they believed it could implicate them in other proceedings.
As well as the coroner’s probe into Mr Maguire’s death, investigations by the Crown Prosecution Service, the Service Prosecuting Authority, the Health and Safety Executive, and army disciplinary proceedings still remain active.
Ms Hassall told the jury it should not “draw any adverse inferences” from any witnesses’ decision to invoke rule 22.
Previously, the inquest has heard that Mr Maguire was hit in the temple by a shot “probably” fired by a fellow soldier attacking a static target 1km away.
He had been standing in a designated administrative area, deemed secure, outside the range where live-fire training was taking place.
However, on the afternoon of May 2 last year, coroner Ms Hassall said soldiers had fired inland.
Cpl MacMahon said: “My role was to keep soldier’s [in my section] safe... I believe I did my job.”
He also told Ms Hassall it was not his role to calculate a safe “arc of fire” — the direction in which soldiers could shoot.
A number of his colleagues told the inquest they believed the safety briefings had been adequate.
Among them were infantry soldier James Murphy and Lance Corporals Lance Dean White and Matthew Stockdale.
All three said following the accidental shooting of Mr Maguire, the command “stop, stop, stop” was given and soldiers were ordered to lay their weapons on the ground in the direction they had been fired.
The hearing continues.