For non-USA residents who don't know, there was an "assault weapons ban" law in effect for many years in the United States, before it expired in 2004, I think.

The original "assault weapons ban" law did not ban the ownership of "assault weapons" that were ALREADY OWNED.

All the law did was ban the SALE of such weapons. So those who owned them prior to then enactment of the law could still own/possess them, but couldn't sell.