It doesn't matter what country, what laws, what restrictions...if someone wants a gun bad enough...there are plenty of ways to get one. If someone is disturbed enough to kill 33 classmates and teachers...nothing's going to stop them.

Countries that have anti-gun laws still have gun crime. Countries that don't have anti-gun laws still have gun crime. Black markets, illegals sales, etc. won't stop because legislatures say 'no more'.

BTW-the US Constitution can and has been amended many times. Nothing is set in stone. If enough of the population wants a change, then there is a process for change.