The facts are that the highest
Firearm Mortality by State are the states with the weakest gun laws. When Australia was very aggressive after a mass shooting in 1996, acting to remove all assault weapons from individuals with just compensation, mass shootings never reoccurred.
It's hard to argue with the numbers and the facts -- but gun fetishists are motivated by emotion. It's also impossible to argue that Australia is not a democracy with freedom.
Again Australia is the sixth largest country in land mass in the world with a population slightly larger than that of Florida, a far more homogenous population than the USA. And we can argue until the cows come home which population enjoys the most liberties, i.e. which government is the least authoritarian. Comparing Australia to the USA is like comparing Topeka KS to New York City.
But we can compare the result of differing cultures.
Roughly 80% of Australian children live in 2 parent homes. In the USA it is less than half.
Australia has far tougher immigration laws than we do and they enforce them, thus somebody in Australia illegally is very rare. In the United States illegals number somewhere between 12 and 20 million.
While three years ago Australia did impose some restrictions on religious groups operating in the schools, Australian kids can attend 30 minutes of religious instruction classes and are allowed to pray openly in public schools and acknowledge and celebrate religious holidays (Christmas, Hannukah etc.) and can bring their Bibles to school with impunity.
Australian school kids are required to get a standard education through high school or, if they refuse or just can't cut it for whatever reason are required to get vocational training up to a given age. Thus virtually all Australian school children are prepared to get a paying job when they complete their formal schooling. And culturally they are expected to do so.
If the situation in the USA was like that, I think we would have a lot less gun violence regardless of the number of guns which is irrelevent.
Only 44% of American households have some some of firearm according to a recent Pew poll.
By comparison in Switzerland, all able bodied Swiss men between the ages of 18 and 34 are expected to do some kind of military service/training and are issued assault rifles or pistols which they are to keep at home. Thus a very high percentage of Swiss households have some sort of weapon, but the gun crime rate there is very low and the school children do not fear mass shootings.
It is not the number or type of weapons that is the problem. Switzerland proves that extremely high levels of gun ownership result in an even safer society. While almost every household has automatic rifles kept from their army training, the homicide rate in Switzerland is roughly 0.3 per 100,000, well over ten times lower than the USA and a quarter the rate experienced in the mostly gun-free Britain.
Until the gun control advocates acknowledge that and are willing to concede we need to change our culture along with adopt sensible gun control laws, the situation is unlikely to change.