Opps, I mis-typed. It would have been better to say transfers instead of buy/sell. Thanks.
The law says;
Part II – Tax on Transferring Firearms.
§ 5811 Transfer tax.
(a) Rate. There shall be levied, collected, and paid on firearms transferred a tax at the rate of $200 for each firearm transferred, except, the transfer tax on any firearm classified as any other weapon under section 5845(e) shall be at the rate of $5 for each such firearm transferred.
(b) By whom paid. The tax imposed by subsection (a) of this section shall be paid by the transferor.
The law says that the seller pays the tax, but I am told that the dealers normally have the buyers write the check so they can send it in with the application.
I guess I am better off quoting the law instead of trying to remember what it says.