Setting: Israel, where a school is being shielded from incoming rockets by a large metal umbrella like structure, built with the intention of keeping school going children alive.
To little avail alas, as the recent attacks targeted primarily children trying to get to school. The weapons used? Home workshop rockets, manufacturing is well withing the capabilities of most amateur rocket scientists, chemists or metal shop operators with a couple of easy instructions. (http://news.bbc.co.uk/2/hi/middle_east/6977346.stm)
The worst school massacre was carried out with explosives, the bloodies attack on a government building used explosives. (Bath school attack,Oklahoma city bombing), not guns.
Even if you deprive them of firearms, people who are bent on killing others will always find a way to do so. So instead of screaming at the NRA, will you -petty please- scream at you child when he or she is showing no respect for authority, has no discipline and/or adheres to a subculture which preaches violence/criminal behavior.
Please teach your children to respect other peoples way of life, and raise them to be a kind person.