nsa,
Tell them to send the rifle back, they pay shipping. Include a statement that the rifle was exactly as advertised and that if the buyer wants to back out for any reason, he is responsible for shipping both ways and any fees involved on both ends and any damage done to the rifle while it was in their control which reduces the resale value of the rifle. Advise them to include a postal money order in the amount of your costs, or a signed, notarized statement authorizing you to cash his payment if you haven't already done so, and refund the balance less your costs. Give him five business days to respond. Send your notice certified mail with a return receipt request. Give them [b]10[/b] days, or at least five business days after you get the receipt back, then cash the the PMO and send them another certified letter advising them that you consider the sale complete.