SA judge calls for total firearms ban

The possession of all firearms should be banned, says a judge who's jailed a man for supplying the pistol a juvenile used to murder an Adelaide teenager.

"The possession of firearms serves absolutely no legitimate purpose in our society," said Judge Paul Muscat in the South Australian District Court on Thursday.

"The sooner firearms are totally banned, the better off our society will be."

No one should be able to keep guns at their homes and if they still wanted to shoot guns they could do so at licensed ranges under strict supervision, he added.

He jailed Charles Alexander Cullen for eight years, with a non-parole period of three years nine months.

The 21-year-old former law student pleaded guilty to supplying the .22 semi-automatic pistol to Liam Humbles, to possessing the gun without holding a licence and refusing to answer police questions about the gun.

He also admitted four counts of trafficking in a controlled drug.

Humbles is in jail for the murder of Lewis McPherson, 18, and the attempted murder of Liam Trewartha and James Lamont.

The trio were walking to a party on December 31, 2012, when they came across Humbles, a 17-year-old acquaintance, who fired shots at them while affected by drugs and alcohol.

Judge Muscat said Cullen was an intelligent man who became addicted to drugs, which he then began to sell to people including Humbles.

After the juvenile was threatened by people in the drug world, he sought to buy a pistol which Cullen sourced from another person for $900.

"I am satisfied you must have foreseen the possibility that Humbles would use that pistol should the need arise," the judge said.

Cullen retrieved the pistol after concerns about Humbles' erratic behaviour, but he "incredibly" returned it because the juvenile had harangued him.

"Our community now lives in fear of offenders armed with firearms," the judge said.

People want guns, but they don't need them.

"The risks associated with allowing people to possess firearms is outweighed by the consequences of their misuse."

While a ban would not stop the proliferation of firearms, it might start to slow it down a fraction and "we start changing things sometimes by fractions".

Outside court, Lewis McPherson's father Mark endorsed the judge's comments about firearms.

"This one gun has just caused so much loss and grief and we just have to keep being tough on them," he said.

"A total prohibition ... maybe one day we might be able to get somewhere close, but in the meantime it is those unregistered and illicit firearms out there that are the concern.

"I would just say to people, hand them in. If you've got them hand them in because it will only end up in grief for you."