After a mass murder in Australia, their government made the ownership, sale, purchase and repair of automatic and semi-automatic weapons illegal. Large capacity clips were also banned. This covered all weapons, including ones already owned.
The government bought back these weapons at 110% of market value.
Coupled with this was an in-depth background check on weapons purchasers. If someone in a home was disturbed, permits could be denied until the magistrate was sure the weapons would be secure.
The Australian Professional Shooters Association (Crocodile Dundee types) supported this saying, "If you need a semi-automatic weapon to kill an animal, you're a city sissy who doesn't belong in the brush."
It worked there, it can work here.