Responsible Firearms Ownership 

               Another fact Americans need to understand is that
               registration is directed to law-abiding citizens, not
               criminals. Not only do convicted criminals by definition
               fail to obey the law, but they are constitutionally
               protected against any registration requirement. In
               Haynes vs. United States, the U.S. Supreme Court in
               1968 ruled 7-1 that compelling registration by those
               who may not lawfully possess firearms amounts to a
               violation of the Fifth Amendment's proscription
               against forced self-incrimination. In other words, the
               court said that if someone "realistically can expect
               that registration [of a firearm] will substantially
               increase the likelihood of his prosecution," the
               registration requirement is unconstitutional.

               Astonishingly as it may sound, some courts have
               ruled that registration of firearms only applies to
               lawful citizens, not to felons. This has been pointed
               out by Legal scholar Don B. Kates in "Firearms and
               Violence - Issues of Public Policy" (1984; pp. 14-21)
               mentioning, for example, the Kastigar vs. United
               States, 406 U.S. 441 (1972) decision. Does
               exemption of felons from gun registration sound
               irrational? It certainly does! Were gun registration to
               be implemented in the United States, criminals and
               felons could very well not be expected to register
               their weapons, since they are already felons
               proscribed from legally owning firearms. Requiring
               them to register their guns, some courts may opine,
               would necessarily incriminate them, and this would
               violate their Fifth Amendment rights.