[2][3] Four days after the killings, Australian Prime Minister John Howard told Parliament “We need to achieve a total prohibition on the ownership, possession, sale and importation of all automatic and semi-automatic weapons.
[1] The NFA placed tight control on semi-automatic and fully automatic weapons but permitted their use by a small number of licensed individuals who required them for a purpose other than "personal protection".
[7] A 2006 study found that in the decade proceeding the gun law reforms, there were no fatal mass shooting and a decrease in firearm deaths, particularly suicides.
[11] In 1998, the Prime Minister appointed the Australian Institute of Criminology to monitor the effects of the gun buyback.
[12][13] A 2013 report by the Australian Crime Commission said a conservative estimate was that there were 250,000 longarms and 10,000 handguns in the nation's illicit firearms market.
[15] Research by Philip Alpers of the University of Sydney found that Australia experienced 69 gun homicides in 1996 (not counting the Port Arthur massacre), compared to 30 in 2012.
A 2006 study led by Simon Chapman, also of the University of Sydney, found that after the NFA was passed, the country experienced more than a decade without mass shootings and accelerated falls in gun deaths, especially suicides.
"[18] Baker and McPhedran's 2007 study has been criticized by David Hemenway, who has written that the authors, who chose 1979 as the starting point for their trend analysis, failed to explain why they assumed the gun violence rate would continue to decline.
University of Melbourne researchers Wang-Sheng Lee and Sandy Suardi concluded their 2008 report, "There is little evidence to suggest that the Australian mandatory gun-buyback program had any significant effects on firearm homicides.
[23] Howard cited this as showing Australia had been right to adopt the NFA but he omitted to mention the same fall in the non-gun homicide rate.
[27] In 2016, Samara McPhedran, a Griffith University academic and chair of the International Coalition for Women in Shooting and Hunting, reviewed the literature on the NFA and homicide and reported that of the five studies she found on the topic, "No study found statistical evidence of any significant impact of the legislative changes on firearm homicide rates.