What's wrong with gun control?

There has been another tragedy today in America. As of writing 4 students are dead, 17 are wounded and the gunman committed suicide before the police could arrive. According to reports the gunman simply walked into the classroom, raised his weapon and open-fired on the students without saying a word.
The gunman has thus far not been named but i'm quite certain that he suffers from a mental disease; whilst this is bad enough one has to wonder how he managed to get ahold of a firearm in the first place. This will be the subject of an intense investigation and will hopefully renew calls for gun control in America.
Whilst most countries have effective gun control, Australia and Britain have each outlawed firearms for the majority of civilians, the United States is the only major Western power not to do so; the reason is wrapped up in it's history and constitution. The United States was formed through rebellion against the British government who they had fled to avoid religious persecution hundreds of years ago. When the constitution of the United States was written in 1787 and the Bill of Rights written in 1789 America was battle-hardened and scars from the recent conflicts with England were still fresh. So an amendment was placed in the Bill of Rights, deemed so important that it followed freedom of speech, and it was:

"A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."

This amendment is arguably the most controversial of all the Bill of Rights; it is cherished by the NRA and worshipped by the militias who consider it their patriotic duty to raise a citizen army.
Yet it is also the clause that allows guns to remain free on the streets of America.
There are several procedures in order to obtain a weapon in the United States. First one must undergo a background check to make sure that you are not a criminal or that you suffer from a mental disorder, after that your weapon must be registered and locked up safely. You're not allowed to bring weapons into certain buildings and some states do not allow weapons to be concealed from public view. Those that follow these rules and regulations are often very happy with their purchase and often during their lives never have to brandish their weapon in self defence. However those that do not acquire their weapons legally are affected by no such stringent rules. Rather for paying only a few hundred dollars on the black market they can acquire handguns, sub-machine guns, assault rifles and the such which have their serial numbers removed to prevent any trace being made back to any other gun owners. These illegal weapons are the cause of many gang shootings in the United States and are untraceable.
Many gun supporters disagree with the outright banning of firearms, rather they say that should firearms be given to all Americans then a shooter would only be able to get a few shots off before being shot dead by a potential victim. This theory is moronic. Gun control works; in all major countries where gun control is effective there has been a noticeable drop in gun-related violence and shootings. Australia, after the Port Arthur Massacre in which more than 30 people died, banned guns outright. There has always been strong support for this position. Many don't wish to see Australia turn out like America, diseased with weaponry. If all citizens were to be given guns it would lead to more death and violence. Removing guns from the hands of potential killers is the only way to severely halt gun violence; whilst there is no way that you can successfully remove guns from a country banning them does make it harder for ordinary citizens to get their hands on them.
The Bill of Rights is not a suicide pact. The outdated amendment is often taken out of its' historical context and that ignorance is the cause of the powerful gun lobby. A greater understanding of the constitution and the outright banning of guns is the only realistic effective gun control.