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The bullets used in the Christchurch mosque attacks were specifically designed to fragment on impact and rip through human tissue.
Trauma surgeon and intensive care specialist Dr James McKay has spoken for the first time about the horrific injuries that the medical staff in Christchurch treated in the immediate aftermath of the March 15 shootings.
McKay was part of a Royal Australasian College of Surgeons submission to a parliamentary select committee in support of the Government's gun law reforms, which propose banning military-style semi-automatic guns and assault rifles.
"We received a total of 48 critically-injured patients in the space of less than one hour, and all had suffered penetrating injuries from what looked like high-velocity projectile weapons," McKay told the committee.
The type of firepower is meant to kill, with hollow-point bullets designed to shred through as much human tissue as possible.
"They are designed to fragment on impact and cause maximum tissue injury. It appears these bullets have also been used as part of the attacks on March 15," McKay said.
The wounds from hollow-point bullets often needed multiple surgeries to clean, disinfect and remove bullet fragments, he said.
"There were significant chest, lung and major blood-vessel injuries which required emergency life-saving surgeries, often multiple times in multiple patients.
"There were multiple abdominal injuries with injuries to bowel and stomach, resulting in significant contamination of body cavities and wounds."
The attack also left many with nerve damage, including to the spinal chord, that have left victims significantly or permanently disabled.
"Overall, high-energy gunshot injuries consign victims to a lifetime of disability both physically, but also mentally and emotionally.
"The physical disability can be devastating for the patient, their livelihood, and their families. Mentally, they'll have constant struggles dealing with - and in many instances reliving - the personal and psychological trauma they have experienced.
"This has been patently evident in the large number of victims we still have in hospital from the March 15 attacks."
He said there were 15 to 20 general surgeons working on victims on the evening of March 15, and many more specialists including nurses, radiologists and psychology teams.
Taking MSSAs and assault rifles out of communities was a public health issue and would improve people's safety, he said.
"Anything that can be done must be done."