Yeah. Its really hard but it better be done sooner rather than later. I dont know what to do either really, but its probably best to start at the roots: do everythings thats possible to prevent new guns on the street. Try to stop the making of guns and the smuggling. It will take very much resources to do but its the only way to do and of course permanent weapon amnesty is also a good idea.
US really do need to have to do something about their gun culture. It is way to much guns, there shouldnt be any at all but since that is quite unrealistic, only cops should have them. There needs to be more action against it.