you are mistaken. Many states have a process whereby a convicted felon can have all rights restored, including the possession of firearms. The federal government recognizes the restoration, and there is a process whereby a person can notify the FBI of same, in order that they may pass the instant background check when buying a gun from a FFL.
Unfortunately for people convicted of federal felonies, such remedies do not exist at the federal level. Thus, Gordon Liddy must have his wife collect guns, he cannot.
Name one and show me the law. More importantly, show me a case whee it has been done.