I think what's getting you tripped up is what the tax represents. The $200 tax doesn't represent ownership, it represents the transfer of posession. To transfer the firearm, you pay the tax. If you sell to an out of state buyer, two taxes are due. You would have to transfer it to your dealer, here is one tax, then once the buyer's dealer gets it, he will have to transfer it to the buyer, here is the second tax. They are $200 each time. Now, if you sell to someone in your own state, you do not have to go through a dealer, and there is only one tax due since it is only one transfer, from you to the buyer.