You are going off on a tangent without knowing jack shit about this shooting.
Let's assume... Let's predict the following:
The shooter was another student who for whatever reason targeted the other student. The reason for purposes of discussion doesn't matter.
Predicting that... Where did the student get a semi-automatic handgun? (assuming it had to be a handgun as he got it into school or on school grounds - article mentions it was a semi-automatic)
Where did he get it? Probably owned by one of his parents. How? Because his jackass parent(s) kept it unlocked and ready by the nightstand, in the night stand, etc... Either that they kept it locked up and the kid knew the combination, where the key was etc.
The problem isn't the firearm. The need isn't more gun control. The solution is taking this parent (regardless of additional offspring in the picture) and charging them with accessory to murder/facilitating a murder and locking them up for ten+ years. Edit: When people see other gun owners paying that penalty, a large number of otherwise responsible gun owners will become actually responsible gun owners.
If my prediction isn't true or even close to true, I'll gladly engage the the normal gun crime banter here...
This is about responsible gun ownership. This is about enforcing stiff penalties for gun owners who do not control the access and safety of their weapons at all times. I say that as a gun owner. I say that as a rabid 2nd amendment supporter. I say that as an owner of scary black rifles. I say that as a parent with a child in my house.