When Australian children were murdered in 1996, we did something about it! We still have guns, but their usage is controlled and registered. You can't get a gun just because you want one.
We certainly don't allow automatic and semi-automatic weapons. What does anybody on the land need with an automatic assault rifle?
If these types had laws had been applied int he U.S earlier many of these tragedies could have been avoided. Because the offenders would not have been able to access guns. Most importantly they would not have been able to get automatic weapons.
If all they could get was a shot gun. These tragedies would have ended very differently.