The Israeli way.
The problems we create for ourselves by declaring gun free zones would be obvious if we were to examine the matter logically. Saying, as if wishing would make it so, that there will be no weapons in a certain place is a denial of the world we actually live in. Only the law abiding observe the laws.
Side note: That looks like an M1 Carbine. It is nearly an ideal weapon for schoolmarms, for it is handy, light and it earns high marks for being easily controllable in rapid fire.
H/T to AZMulder77 on Twitter for posting a link to the picture.