A picture is worth a thousand words. Mass shooting statistical graphs can as well. My intention was not to stir up a particular way of thinking, but rather to illuminate the facts without imposing a biased view.
In summary, we in the U.S. are a violent (albeit less so in recent decades) people, more so in the south and east, with the amount of guns in homes declining, and yet incidence of mass shootings and victims remain steady.
Below is a picture of deaths due to injury by firearms. The obvious fact is that, for the most part, the southern part of the U.S. has more deaths than the north, northeast, and west.
Below is a graph of the mass shootings in the U.S. Most killers obtained their weapons legally.
Below is a graph of mass shootings per year and the victims in the U.S. The amount of mass shootings and victims varies from year to year, but on the average has not changed for the last several decades.