Veteran accused of shooting former bikie

A WA veteran has gone on trial for shooting a former outlaw bikie, claiming he was defending himself while confronting him over suspicions he set his car ablaze.

James Stephen Callaghan, known as Jim or Jimbo in his small hometown of Koorda, is fighting a charge of murder laid after he fatally shot his former friend Gavin McMaster in February last year.

Today, a Supreme Court jury was told the shooting had come after the men's friendship soured and Mr Callaghan suspected Mr McMaster of setting his ute on fire one night.

Prosecutor Laura Christian said in her opening address that the State alleged Mr Callaghan responded to finding the blaze in the early hours of the morning by arming himself with a rifle and parking outside his victim's house.

Ms Christian suggested the accused man had decided there was only one solution to his trouble and that was to kill Mr McMaster.

The prosecutor said Mr Callaghan, who knew of Mr McMaster's bikie past including shooting two people, had walked to the back door with his rifle, prompting Mr McMaster to throw a tomahawk at him.

Ms Christian said the accused man had then lifted the rifle and fired, with the bullet going through a cupboard before lodging in Mr McMaster's thigh.

Mr Callaghan fired another two bullets striking Mr McMaster in his back.

"The shooting has nothing to do with self defence," Ms Christian said, telling the jury that ballistics and blood spatter experts would support the State's case.

But defence lawyer Philip Urquhart argued his client's actions were purely self-defence.

Mr Urquhart asked the jury to imagine finding their car on fire, with the "prime suspect" known to them as someone younger, bigger and stronger who had been a member of an outlaw motorcycle gang and previously shot and injured two people.

"You also know that this man has it in for you.... (and) regards himself above the law," Mr Urquhart suggested.

The lawyer said his client had gone to Mr McMaster's home with his rifle deliberately pointing to the ground and it was after he saw Mr Callaghan wielding a tomahawk and throwing it at him that he had fired a shot "purely in self defence".

He asked the jury to put themselves in the accused man's shoes, and not knowing if he had hit Mr Callaghan before firing twice more - again in self defence.

Mr Urquhart said the law defined self defence as an act done when a person believed it was necessary in order to protect themselves against harm - even if the harm was not imminent.

This act had to be a reasonable response in the circumstances as the person reasonably saw them.

The trial continues.