Just make possession a very severe crime with harsh penalties like having a full auto assault rifle in The US without a license.Very few people in The US have an illegal fully automatic assault rifle because they know if they are caught with one they are doing serious time.Crimes committed in The US with fully automatic assault rifles is also virtually non existent.
There aren't hundreds of millions of fully auto weapons in circulation. This isn't a fair comparison of anything.
You can't make possession of guns a severe crime because its is constitutionally protected.