For clarification purposes the firearm known as the Ruger MK III pistol is manufactured to standards that make it legal for sale in California, Massachusetts and the District of Columbia this making it eligible for ownership in United States territories with the most restrictive laws governing all aspects of firearms.
It is chambered for .22 rimfire ammunition which is recognized as one of the most low-powered calibers available for purchase.
While it is capable of accepting detachable box magazines and can be loaded immediately there are no manufacturers that have made a magazine capable of holding more than ten rounds of ammunition.
Both the mother and the father have records for domestic violence with the father going further having served a prison term for attempting to murder his wife. The student who did the shooting was 17 at the time. This means all three members of the family were disqualified from firearms ownership under federal law.
It would seem that there are no excuses that can be raised in this matter. Rather any discussion that can be raised must be aimed at the student himself and not any other factors.
If one cannot have an argument without resorting to hyperbole, name calling and emotional rhetoric, then they have lost the argument from their first post.