Giving evidence by video link from Melbourne in the trial of David Bain, who is accused of murdering his parents, two sisters and brother in 1994, Prof Stephen Cordner, director of the Victorian Institute of Forensic Medicine, said people occasionally shot themselves on the side of the head which was not their dominant "handedness".
He said he agreed with Dr Alex Dempster, the Dunedin pathologist who carried out the Bain family post mortems, that the head wound of David Bain's father, Robin, was a contact or near-contact wound.
He disagreed with two Crown pathologists, Emeritus Professor James Ferris and Dr Kenneth Thomson, who both said the wound and the surrounding skin had the characteristics of an intermediate or even a distant wound.
Prof Ferris had highlighted what appeared to him to be "stippling" or tattooing, a defining characteristic of an intermediate distance wound.
But Prof Cordner said his view was that the marks Prof Ferris and Dr Thomson thought were stippling were probably blood spots, skin defects or even a hair follicle.
They were "too indistinct and imprecise" for him to say they had the characteristics of stippling, and it would be "wrong to find that's what it is", he told the court.
The features of a contact wound - blackening from soot, the effects of heat, and bullet wipe resulting from material from the barrel or the bullet - were all present around the margins of Robin's wound.
Prof Cordner's evidence supported that of UK Home Office pathologist Dr Robert Chapman, who last week said he believed Robin's wound was either contact or near contact and was compatible with suicide.
Cross-examined by Crown counsel Cameron Mander, Prof Cordner said he was aware of a study of 51 gunshot suicides which found four used the left temple and 11 the right temple.
He was also familiar with an American research paper reviewing 1704 firearm suicide cases.
That research found that of 210 who committed suicide using a rifle, 48 shot themselves in the right temple and seven in the left temple, the least favoured site apart from the abdomen, which was used in only four cases.
In percentage terms, that was 3.3% left-temple shots compared with 22.9% for the right temple but it did not discriminate between right and left-handed people, Prof Cordner said.
However, it was not true that suicides always shot themselves on the side of the head which was the same as their dominant hand, he told the court.
Earlier, Prof Cordner gave evidence that David Bain's sister Laniet could have survived long enough after she was shot to make gurgling noises.
Bain told the court at his 1995 trial that he heard Laniet gurgling.
The Crown says Bain had to be the killer as the sound could only have occurred after Laniet was shot in the cheek, a wound all the pathologists agreed was survivable.
The next two shots were fatal.
But Prof Cordner said it was difficult to make physiological conclusions about even severe brain injury.
He could not exclude the possibility Laniet would have survived for some time - "not very long" - after receiving all three wounds.
But he accepted the evidence of Dr Thomson and Dr Chapman that she would not have been capable of any voluntary movement after the two severe injuries.
Another Melbourne specialist, Peter Ross, of the Victorian Police Forensic Science Services, who was a scientific adviser in the Azaria Chamberlain case, was the last witness called yesterday.
His evidence, relating to ballistics issues in the case will be completed today.
• Defence counsel Michael Reed, QC, said Mr Ross would be the last of the more than 50 witnesses the defence was calling, although British fingerprint expert Carl Lloyd is to be cross-examined on a video link, probably tomorrow.
Mr Lloyd gave his evidence in chief last week.
