I think an alarmed "gun safe" mounted in a way that it cannot be removed from the building in at least two locations would not be unreasonable. You would stock these with laser site semiautomatic rifles firing frangible rounds(designed to break up on impact without over-penetrating what they hit)PLUS some sort of easily seen identification authorizing possession of the weapon. The only access would be thru codes known only to trained personnel willing & able to take this responsibility. The "alarmed" would (1)apply to each individual having a unique access code in order to track contact with the weapon, (2)for cleaning/maintenance/security check require an additional code to be entered to prevent the alarm activation. Codes would have to be reentered when weapons returned to safe, (3) Any tampering to the exterior of the safe, or access without dual code mentioned above would trigger "active shooter" & "lockdown" to the school itself & the first responders via 911, (4) location of safes on "need to know" basis & not necessarily in obvious locations (i.e. - janitor closet vs. principal's office, etc. ) Like everything else it's up for reasonable discussion. TSA anyone?? (T_he S_chool A_rmy)