The danger here is the media, which sees ratings in the deaths of these poor souls and always hated guns to begin with. Seeing as most of the American media is state-run for all intents and purposes, we can expect a narrative wherein the noble Democrats righteously seek to strip the awful "assault weapons" from evil Republicans who seek to sow carnage with them.
This is where everything we've learned about gun rights must be employed in representing ourselves as a community (a community that virtually never includes these sort of psychopaths, who often just pick up the gun right before their evil deeds). Our representatives must be lobbied, and perhaps more importantly, held accountable for their actions. There might be some dark days ahead for gun owners, but the future is not yet written.