A man acquitted of plotting to blow up an Adelaide electrical substation has been jailed for almost five years on 22 firearms offences.
But Artem Vasilyev, 27, who has been in custody since September 2021, will be eligible to apply for release after Justice Sandi McDonald set a non-parole period of three years.
A Supreme Court jury in June found him not guilty of committing other acts done in preparation for, or planning, a terrorist act, between July 2020 and September 2021.
Police had raided the home that the former Defence employee and electronics engineer shared with his mother, seizing an improvised AR-15 semi-automatic firearm produced by a 3D printer.
A 3D printer was also found, along with a printout containing the methodology to manufacture firearms.
Hard drives on the PC contained documents on firearms, explosives, how to avoid or escape detection, and nationalist and racist ideology, the court was told.
Justice McDonald said Vasilyev was aged 12 when his parents migrated to Australia from Russia, and gun culture had been part of his upbringing.
He had been socially isolated and lonely throughout his life and the death of his father in 2016 had an "enormous impact" on him.
In a report to the court, forensic psychologist Loraine Lim found Vasilyev was likely to be a "high-functioning autistic person" with undiagnosed autism spectrum disorder and he was a low risk of committing violence, firearms and extremist offences in the future.
"Dr Lim formed the view that your interests in extremist ideologies had extended beyond mere curiosity ... in her opinion, you were someone who was in the process of becoming radicalised," Justice McDonald said.
"She opined that it is likely the radicalisation process was prematurely terminated by your arrest."
Dr Lim reported that Vasilyev spoke in long monologues and had "a very unusual, precise manner of speech that is uncommon even for non-native English speakers".
He told her that in prison "I've been called a robot, or Sheldon from the Big Bang Theory".
Vasilyev believed that his social skills had improved significantly while in prison, "because it was a 'sink or swim' situation, you had no choice but to make friends, because the only alternative was to sit in your cell alone".
"You remarked that for the first time in your adult life, you've made some good friends who are supportive of you and who celebrated with you when the jury found you not guilty of the terrorism charge," Justice McDonald said.
Vasilyev's offending must also be considered in the context of the lifestyle he was living, she said.
"You told Dr Lim there were days when you would wake up and get through the entire day without speaking to anybody else," she said.
"When you're released from custody, you'll face even greater challenges. In addition to being socially isolated, you will have lost your employment, your reputation, and the few social contacts that you previously had in your life.
"It cannot be overlooked, however, that you are someone who is prepared to come on board so quickly in espousing an ideology that most members of the community would find abhorrent."
She sentenced Vasilyev to four years and nine months in prison on the 22 firearms offences, backdated to September 2021, and recorded a conviction but imposed no penalty for a breach of bail.
