Ok so I've got an ar15 barrel I'm in the process of turning down to 13" (before anyone jumps on me, I have NO intention of mating it to an upper until I have all my t's crossed and i's dotted) and I want to know how to get the paperwork started to get the SBR tax stamp. I am planning on mating the barrel to an existing rifle I have, just a simple barrel swap. And I put in for more than one tax stamp at the same time? If an AOW stamp is only $5, I figure making a serbu-shorty-style 500 or 870 can't be that hard, but I'm really not sure what the laws are concerning "manufacturing" one as opposed to "buying" one. I know this can be confusing ground and I get a thousand different answers when I try googling it, so input from members who have gone through the process would be great. Thanks guys! By the way I'm an Oregonian, not a Washingtonian, I'm sure that makes a difference.