Laws only restrict the law abiding. Criminals will not be effected by gun laws, and thinking otherwise is blatantly illogical. Therefore there must be a reason for these laws, and it certainly isn't to stop criminals from buying guns. What do you think the actual reason might be? It isn't to punish those that use guns in crime, prosecutors are notoriously lax when prosecuting firearms charges (against criminals). Further we know from studies done on the NICs system, that attempted gun purchases by disallowed individuals is rarely prosecuted.
What they want is a registry followed by confiscation, as that is what ALWAYS follow registration.