Unfortunately your constitution doesn't stop psychopaths from buying large amounts of semi-automatic weapons (converting them to fully automatic), and then going into a hotel room and shooting dead dozens of innocent people!
Stricter gun laws made by your government would go some way to stop gun shops being so quick to sell their products to just any unbalanced wacko!
Nor does it prevent a wacko from renting a truck and driving it through a crowd, killing the same number of people. Nor does it prevent a wacko from using a drone to drop a pressure cooker bomb in the middle of a crowd.
The problem is not the weapons, it's identifying wackos and getting them the treatment that they need. Any ideas on how we do that?