All of the issues you describe exist in all countries, the too easy availability of guns in this country is THE salient difference.
Describing the availability and misuse of guns in the U.S. as a 'misuse of tools' is fatuous.
'Well regulated' is in the Amendment. Unevenly regulated in a population of 330 freely moving people is decidedly not what the founding fathers wanted.
We point out a problem with almost anyone owning an AR-15 or weapon like this, we hear the argument from republicans that they need a gun like this for hunting varmints
We just like to keep pointing out that it is the choice weapon to use when you want to have someone use it to mass murder a lot of Americans. Republicans say no, and then it happens again.
But like you stated, how are you going to know, so don't do anything, who gives a shit if Americans keep dying by the 1000s, and the American economy suffers, just do not take those AR-15s away. If anything, let us make them more available, like here in Tennessee.