The ship has sailed on the number of guns in the public. The Constitution did it's purpose, it armed the citizenry and this country isn't putting that genie back in the bottle. The posts by @Cold Miser and @amarshall are a place we should be at as a society though. Waiting period, background checks, maybe we need to throw some money at the permitting side of things.
We aren't eradicating mass shootings in the US, but even a 50% reduction would be a win and a step in the right direction. There are things that can happen that allow access to guns for the "adults" of society.