Christopher James Millington, 33, was sentenced in the ACT Supreme Court on Tuesday afternoon to seven years and seven months behind bars.

Justice David Mossop set a non-parole period of four years and two months, nearly half of which the Comanchero associate has already served on remand.

The judge said Millington had been among three or four disguised intruders who broke into the Kambah home of Alexander Miller, the Canberra Nomads' sergeant-at-arms at the time, in November 2019.

Millington and his co-offenders, including Aofangatuku Langi, a senior Canberra Comanchero bikie, busted down Miller's front door as the victim and his then-girlfriend raced to the bathroom and took cover.

A listening device police had earlier installed in the house captured one of the intruders saying "come out, c---", followed shortly after by "f--- it, discharge at him".

Millington, who was armed with a gun, fired a single bullet that officers later pulled out of the doorframe between the home's bathroom and laundry.

The intruders then poured petrol around areas that included the living room, and someone said "light it up" before it was ignited and the offenders fled.

Millington, who was arrested and remanded in custody in February 2020, pleaded guilty to some charges but contested others at an April 2021 trial.

He admitted aggravated burglary, arson with intent to damage property, and discharging a firearm in an act endangering life.

At the conclusion of his trial, a jury also found him guilty of arson with intent to endanger life and attempting to destroy or conceal evidence.

Justice Mossop said Millington had committed the latter offence by arranging to have his Mazda, which had been used to transport the home invaders to and from the scene, scrapped upon hearing Langi had been arrested.

The judge accepted the submission of Millington's barrister, Beth Morrisroe, that the 33-year-old had been primarily motivated by a personal feud with Miller, who had torched the offender's Mercedes.

The court heard Millington had reported committing the offences out of anger, a desire for retaliation, and fear for the safety of his family after Miller allegedly threatened to shoot at his parents' house.

Justice Mossop said a listening device installed in the Mazda in the lead-up to the incident had also recorded Millington and Langi discussing plans to attack Miller.

"I want to f--- him up so he has to live with it, man," the 33-year-old said at one stage.

"Cut his f---ing fingers off, man."

Crown prosecutor Anthony Williamson accepted Millington's "desire to seek revenge and retribution" was his main motivation.

But he suggested outlaw motorcycle gang activity still had a part to play in the attack on Miller, who had joined the Nomads after being turfed out of the Comanchero over a perceived lack of loyalty.

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While he conceded Millington had not been "on any trajectory to become a patched member" of the Comanchero, Mr Williamson said the offender must have a similar mindset to fully fledged bikies like Langi.

It would be "incomprehensible" to suggest any different, he told the court, saying Comanchero members would not otherwise have invited Millington to regularly "hang out", party with them and attend their clubhouse.

Justice Mossop, who described Millington's prospects for rehabilitation as "guarded", ultimately imposed the lengthy sentence of imprisonment.

He backdated it to account for time already served, making Millington eligible for parole in April 2024.

Millington, who wore prison greens, wrote copious notes throughout Tuesday's proceedings but did not show any emotion upon hearing the sentence.

He is currently incarcerated at the Goulburn Correctional Centre, having been transferred there after he allegedly threatened a guard at Canberra's Alexander Maconochie Centre.

The court heard on Tuesday that Millington denied having made such a threat.

Langi has previously been jailed for seven years and three months over the Kambah home invasion. He is also eligible for parole in April 2024.

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