Does registration work?
Gun laws in Brazil. In Brazil, all firearms are required to be registered with the minimum age for gun ownership being 25. It is generally illegal to carry a gun outside a residence, and a special permit granting the right to do so is granted to certain groups, such as law enforcement officers.
According to most sources, Brazil possesses high rates of violent crimes, such as murders and robberies; depending on the source (UNDP or World Health Organization), Brazil's homicide rate is 20-30 homicides per 100,000 inhabitants according to the UNODC, placing Brazil in the top 20 countries by intentional homicide (source wiki)
They had nearly 60,000 murders in Brazil last year.
America has about 5,500 firearm murders.
Then there's Chicago, Baltimore, DC, California. All lead the US in murders but also strictly control firearms.
It sorta worked in England and Australia, in the sense it reduced gun crime. However, other forms of violent crime went up by over 80%