While there are proposals to restrict the supply of guns to criminals, none have ever proven effective, just like similar prohibitions on illegal drugs or alcohol have failed. All they do is burden law-abiding citizens.
Thus we need to concentrate on reducing the demand for guns by criminals. In the 1920's, kidnapping of the wealthy for ransom was a major problem. It no longer is because kidnapping was then made a Federal capital crime. Thus criminals know that the penalty far exceeds any expected gain from the criminal act and avoid kidnapping people.
Similarly, if criminals knew that carrying a gun during a break-in or robbery would subject them to the death penalty, they would stop carrying them, as the penalty would exceed any benefit of a gun as a criminal tool.