Australia tries to implement national gun registry

Ever since the Port Arthur massacre three decades ago, Australia has had strict gun control laws. The mass shooting prompted then-Prime Minister John Howard to fundamentally reform Australia's gun laws, including a complete ban on semi-automatics and shotguns. But there was no registry for those who still owned weapons. The World's Sarah Birnbaum says the recent killing of two police officers is behind a current push for a national gun registry.