That law increases a gun possession sentence if a felon's previous crime was for violence or drugs, but not if the state has either granted a pardon or restored the felon's civil rights. Restoration of rights, including the right to own guns, is a procedure used by many states after a felon successfully completes parole.

Palmer pleaded guilty to concealing his criminal record and giving other false information when he bought a rifle from a licensed dealer in Tacoma, Wash. in October 1976.

U.S. District Judge Jack Tanner sentenced him to more than twice the sentence originally recommended by prosecutors, based in part on the fact that one of his past crimes was a 1989 conviction for possessing marijuana with the intent to distribute.

But the appeals court said the state of Washington had later restored Palmer's civil rights for that conviction. Although the U.S. Sentencing Commission's guidelines would allow the conviction to be used to increase the sentence, the guidelines conflict with the underlying law, said Judge Sidney Thomas in the 3-0 ruling.

The court also said Tanner had wrongly found Palmer responsible for owning a number of guns that actually belonged to his son, another basis for an increased sentence. The net effect is that his new sentence will be no more than 18 months, a period he has already served, said Assistant Federal Public Defender Peter Offenbecher.