A failure to follow Army safety requirements, as well as time pressures and inexperience, all contributed to a "shambolic" live-fire exercise that killed a soldier, an inquest has heard.

Key points: Exercise Tigers Run did not follow Army safety doctrine, inquest hears

Exercise Tigers Run did not follow Army safety doctrine, inquest hears Officer in charge of exercise was junior and faced time pressures

Officer in charge of exercise was junior and faced time pressures Army blames commander's assessment of staff competency for failures

The inquest has been examining the fatal shooting of Geelong man Jason Challis, 25, during an urban live-fire exercise known as Exercise Tigers Run at Mount Bundey Station about 130 kilometres south-east of Darwin on 10 May, 2017.

Private Challis was behind a plywood building directly in line with a "dummy" target on the other side of the wall when he was shot in the head and leg.

Lieutenant Steven Cross was the officer in charge of designing and supervising the exercise, and gave evidence on Wednesday that he was a "junior lieutenant" with little supervision at the time.

"I do feel like there wasn't any influence or assistance, I guess, from anyone above me," he said.

Lieutenant Cross said his commanding officer Lieutenant Colonel Paul Shields made it clear that blank ammunition would not be available for a required blank run-through.

"The [commanding officer] was sick and tired of hearing people say they can't do anything," he said.

"I did everything in my power… but I was directed by my chain of command that it wasn't going to occur."

The family of Private Jason Challis arrive at court in Darwin for the inquest into his death. ( ABC News: Jason Matthews )

Range preparation time halved

At the time of the incident it was mandatory to conduct "dry-run" rehearsals and a run-through with blank ammunition before an urban live-fire exercise, said counsel assisting the coroner Kelvin Currie in closing submissions.

There was no blank ammunition available for the exercise, and the section Private Challis was in did not have a dry rehearsal, the inquest heard.

"If even a dry rehearsal had been conducted, it is almost inconceivable that Private Challis would have been in the danger zone behind a target," Mr Currie said.

"What is clear is that it was not a lack of appropriate doctrine that was the issue. It was a failure to follow the doctrine."

Mr Currie told the inquest it had been "a shambolic start" to the exercise, after an initial pause in the training because of safety concerns and soldiers missing their target.

Lieutenant Cross also gave evidence about time pressures on the exercise, which preceded Exercise Southern Jackaroo with US and Japanese forces.

"I was initially given two days to conduct the range, and the morning of I was told I had one," he said.

"I don't know why I was cut down by one day, but I was annoyed about it."

The inquest heard it was Lieutenant Cross's first time designing and supervising a so-called Category C urban live-fire range, but he believed it was a "great opportunity".

Consistent with evidence from other witnesses during the inquest, Lieutenant Cross said a live-fire range training course he attended did not focus on urban live-fire safety procedures contained in Army doctrine, known as "Annex K".

"Annex K isn't really stressed on the course," he said.

Sorry, this video has expired A reconstruction of the shooting incident during Exercise Tigers Run

Commander's ability to assess staff 'deficient'

According to a statement from Lieutenant Colonel Paul Shields which was read aloud during the inquest, a "default mindset" existed within the Army not to disclose the tactical setting of live-fire practices to participants.

"It is common practice to predominantly seek to exercise our commanders and soldiers in a dynamic setting — having teams conduct activities on the objective live without having seen or rehearsed their actions on the actual range," he said.

"This default mindset runs counter to the risk mitigation measures outlined in Annex K, which require dry walk-throughs followed by blank rehearsals on the buildings utilised for the practice."

Lieutenant Colonel Shields also said Mount Bundey was not accessible for "reconnaissance activities and detailed planning" prior to Exercise Tigers Run because of "heavy wet season environmental impacts".

The inquest heard Lieutenant Colonel Shields was no longer with the Army.

'It's a clusterf***'

Defence Force counsel Fiona McLeod SC told the inquest the Army accepted Private Challis's section did not complete either a dry-run or a blank rehearsal, as required.

"The live question is whether the members in the activity were competent and qualified," she said.

Ms McLeod said the "accepted failures" reflected deficiencies in the commander's ability to assess the competency of staff, including the officer in charge.

"The Army does not accept the characterisation that this exercise was shambolic or that there was chaos on the ground," she said.

She said Army had put in place a new range safety team and an annual qualification requirement to demonstrate understanding of Army doctrine.

Counsel assisting the coroner recommended "proper dissemination and training" related to all Army safety documentation.

Coroner Greg Cavanagh said "shambolic" wasn't the only word that could be used to describe Exercise Tigers Run.

He referred to a scene in the movie Heartbreak Ridge, where Clint Eastwood's character is asked to describe a marine operation: "It's a clusterf***," he said.

The coroner expressed his sympathy to Private Challis's family.

"I'm glad it's not my son," he said.