But 'gun control' as being discussed in this thread is an American problem and it begs an American solution. The political culture in America is quite different from that of Europe or Australia and we cannot simply 'wish' the differences away. We cannot just apply the context of another society/country onto them; as the Americans have their own norms, values, and laws. Without due regard to the American context (at Federal and State level on laws relating to gun ownership), we will not get much further -- and this current discussion has the potential to become a discussion about their values vs your values or their laws vs your laws.
Indeed, as OPSSG mentioned this issue of gun violence is one the US faces, and it is important that suggestions be made within the social, political, and legal context of the US.
Some things which are important to know/understand, so that the US context can be better understood or appreciated.
Roughly a third of the worlds' small arms are within the US/US ownership (~300 mil. small arms of various types). That works out to there being enough guns within the US for every man, woman and child to have their own.
Further, the numbers I have seen suggest that while US gunowner households are a "minority" population (i.e. less than 50% of US households have a firearm), it is a sizeable minority (~40% or so). Going further with that, ~20% of households with firearms own ~65% of all US firearms.
In strictly practical terms, making a significant decrease in the number of firearms owned within the US would be difficult, just due to the sheer numbers. As an example of what I mean, there are ~10 mil. firearms in neighbouring Canada. If the entire inventory of Canadian guns were to double, with the extra guns coming from the US, that would only cause a ~4% decrease in the total US gun inventory.
It also must be understood that the US has social, political, and legal traditions which support private ownership of firearms, along with the concept of ownership for self-defence and defence or property. Part of the US gun tradition also stems from the Colonial period of the citizen-soldier. At the time the US was founded, it was decided that the government would rely upon various state militias which could be called up as needed, instead of there being a standing national army. This was itself an extention of, and outgrowth from the War of Independence fought with Britain, as well as the English Civil War which was fought at a time many of the colonies were being first founded. At the time, Parliament needed to meet at least every two years, because it was prohibited for the Army to be funded for longer periods. When Parliament met in session, it would then vote for the continuation of funding to sustain the British Army. The US in the early days after becoming independent, under both the Articles of Confederacy as well as the Constitution of the United States, followed a similar provision, where Congress (being the Legislative body and having budgetary authority) met annually, and each year needed to budget for the regular Army, being unable to vote on a budget with a duration longer than a year.
However, the US (Legislative and Executive branches) took things further, in that the standing regular Army was just 700 troops scattered up and down the Atlantic coast in the thirteen founding colonies and their territories. The actual role of the Army regulars was not to serve as a unit formation, or even act as a cadre. The regulars were instead stationed at various Federal armouries and arsenals, and they were tasked with acting as guards to protect the warehoused guns, cannon, powder and shot in peacetime. In the event of hostilities, the regulars were then to oversee the distribution of the Federal arms to the local militia units, essentially acting as Ordnance and Stores personnel.
Fast forward two hundred years though, and it is now felt that part of the reason for the 2nd Amendment to the Constitution of the United States was to prevent the government from being able to disarm the populace, leaving the populace without the means to rise and overthrow the government, like was done to found the US.
In many respects, it is that later belief/tradition which causes problems in terms of gun control, as adherents tend to view the government with suspicion and as a (potential) threat. Believers tend to view attempts at gun control as the government attempting to limit their ability to resist government actions. They also want to make sure that they have weapons which would be most/best effective in fighting against the government, if thing came to that. This is part of the reason for the popularity for military style weapons, as such weapons are really designed for use against humans.
If, over the course of generations, there starts to be a marked notice in interest in firearms within the US, then perhaps there could be significant gun control movement. Otherwise though, I suspect it would be better to focus more attention to tweaking specific elements of gun control, as well as non gun control efforts.
One other thing which IMO is important to consider, is that while gun control efforts could lead to a reduction in gun deaths, they might also just induce people who wish to cause mass harm/terror to use a different mechanism, something other than a firearm.
-Cheers
