I would double check with your lawyer on this but it appears Oregon lists what is a weapon for purposes of the "felon in possession statute" ORR 166.270.  In that statute it lists a firearm, any instrument or weapon having a blade that projects or swings into position by force of a spring or by centrifugal force or any blackjack, slungshot, sandclub, sandbag, sap glove, metal knuckles or an Electro-Muscular Disruption Technology device as defined in ORS 165.540, or who carries a dirk, dagger or stiletto, commits the crime of felon in possession of a restricted weapon. Remember that lawyers are very good at arguing that an item not necessarily on this list could be considered one of these for their purposes if you are found with one.