Well, the term "mass shooting" as used in this country is erroneous. It was introduced by the media to apply to what are more accurately multiple homicides.Hmmm, funny thing, much of the pro gun crowd would not consider this shooting to be a mass shooting because it is a familial murder suicide. So the US pro gun groups usually overlook the very numerous sorts of mass shootings like this as not being mass shootings, but yet when it happens in a more anti-gun country, it is now a mass shooting. Interesting.
Singular example are hardly proof that something is or is not working. The information has to be taken in context. Does Australia have a bunch of mass shootings?
Google "4 people shot," "6 people shot," "6 people shot," "family murder suicide" etc. and see how many we have going on here. Is that therefore proof that our pro-gun laws are not working?
Correctly, a "mass shooting" is something that occurs in a despotic dictatorship etc where a neighborhood or community is massacred.
This is something the "pro gun" society has allowed to take place without any opposition. The term should have been met with ridicule from the get go.