These kinds of things are going to happen with increasing frequency. When they get bored with trashing their own inner-city environs, they'll move out to the burbs and more rural areas. I'll be keeping my AR and "high capacity" mags.
I have a scoped rifle in .308 in a strategic look-out place on the second floor of my home for just such a situation.
That may be true on a national level, but it certainly isn't true here in Indy.