ACT Supreme Court Justice Hilary Penfold jailed James Anthony Eimerl for four years and eight months for his part in the hold-up and unrelated older offences.

Eimerl and his partner-in-crime, Joseph ''Jack'' Patrick Carbone, were 19 years old when they robbed the man of $35,000 during a daylight heist at the Florey shops last July.

During the robbery Eimerl pointed a replica pistol at the victim and appeared to cock it, as Carbone said, ''Just shoot him''.

The pair were later found hiding under bushes nearby along with the backpack filled with cash.

Taking into account time served Eimerl, who the judge said ''took the lead initiating the robbery'', will be eligible for release in September 2013.

''I don't claim to understand what's been motivating you over the last couple of years,'' the judge told Eimerl yesterday. But she said without ''some serious changes to your attitude'' he could expect more custodial sentences.

Carbone was sentenced to two years and six months but released from full-time custody after taking into account seven months served.

The robber, who the court heard showed remorse for his crime, will spend his weekends locked up for another 12 months and then serve a suspended sentence.

''I hope this whole experience has given you a fright, and by the time you finish your sentence you will be ready to move on into a different kind of life that doesn't involve illicit drug use ... but does involve choosing your friends more carefully,'' the judge said.

She noted that both men came from loving, supportive families, but expressed disbelief about their claim the crime was ''spur of the moment'' and opportunistic. Eimerl and Carbone gave different reasons for being at the shops that day, but both said they were desperate and indebted to a drug dealer.

Their victim was not wearing a uniform, driving his own car and carrying the takings of several stores in his backpack at the time of the robbery. The judge also noted the pair were arrested in possession of the replica pistol and the knife.

''I make no finding that the offence was premeditated ... nor do I accept the claim that the offence was a spur of the moment action driven by desperation,'' Justice Penfold said.

Both men spoke of substance abuse issues with the authors of presentence reports. However, the veracity of Eimerl's claims were questioned after he asked the author to ''make me look good''.

''Apparently I have [Justice Richard] Refshauge and he likes to hear about rehab things,'' he said at the time. ''He doesn't like putting people with drug problems in jail. So you need to tell him that I have a drug problem.''