A Dunedin man who shot his victim with a crossbow from near point-blank range has had more than a year axed from his sentence.

Shaun Michael Hartstone, 26, was jailed for nearly six and a half years when he appeared before the High Court at Dunedin a year ago, after admitting the vigilante attack which stemmed from the theft of his motorbike.

But in a decision released today, the Court of Appeal said the sentence was too stern and too little regard was given to the defendant’s mental-health issues.

Hartstone’s prison term was adjusted to five years four months.

The 38cm arrow lodged in the abdomen of the 54-year-old victim. Photo: Supplied

A dispute between him and the victim began on April 9 last year when he discovered his Honda trail bike, which had been stored in the 55-year-old victim’s Concord garage, had been stolen.

Over the ensuing weeks, Hartstone shot fireworks at the garage of the man’s home and yelled abuse from his vehicle.

After one of the incidents, the victim found a window of his van was smashed and there were two broken arrows inside.

Finally, on April 23 that year, Hartstone returned, wielding a high-powered crossbow capable of firing an arrow at 300 feet per second.

The victim armed himself with an axe and emerged from the garage with an associate.

With the man only a couple of metres away, Hartstone shot him with the hunting weapon.

The “bullet-point arrow” became embedded in the victim’s torso but did not penetrate any major organs.

He was discharged from hospital the same day.

“The c... deserved to go in the ground,” Hartstone later told police.

Justices Ellis, Mander and Gault stressed the dangerousness of the incident.

The crossbow didn't penetrate any major organs and the man was discharged from hospital the day of the incident. Photo: Supplied

“The high-powered firing of an arrow at a person from around two metres away undoubtedly brought with it the possibility (if not the likelihood) of serious and even fatal injury. It was largely fortuitous that the victim in this case was not more badly injured,” the ruling said.

While there was no great planning involved in the attack, the court noted Hartstone had spoken to associates about shooting the victim.

At sentencing, reports outlined how the defendant had exhibited behavioural and learning difficulties from a young age and was intermittently placed in care.

He also suffered a head injury when he was 3.

The sentencing judge accepted Hartstone’s ADHD predisposed him to volatile behaviour but stressed he had stopped taken prescribed medication in the lead-up to the crimes.

However, at the appeal a psychiatrist provided evidence that the shunned medication was actually to address the defendant’s occasional psychotic symptoms.

“The rate of ADHD amongst prisoners has been described as ‘disproportionately high’ and a variety of causal connections between ADHD and offending have been identified,” Justice Rebecca Ellis said.

“It follows that it seems very likely that there was a greater causal link between Mr Hartstone’s ADHD and his offending than the judge thought.”

In the circumstances, the Court of Appeal ruled the sentence was manifestly excessive.

Hartstone is understood to be eligible for parole at the start of next year.