Well, better somthing than nothing.
If the automatic weapons bans stops the mass murders, even when they are few, it already saved lives, so its worthy.
If a law saves one life, its already worth it IMO.
Now, i think all weapons should be banned from civilian use, even those that use compressed air. Civilians should not use weapons in my point of view, and the security should be in charge of professionals.
I do realize that my point of view breaks the second ammendent of the USA and i dont expect USA to apply my view any time soon, but its my opinion.