Look here's what I'm going to do as we're both in the same situation with this guy except he paid me $200.
I'm going to relist the gun. If and when it sells, I'm going to keep the amount that Tx_Aggie paid into my paypal account in there. If/when he resurfaces I will refund him. If an arbitrary long-*** amount of time passes without him (6 months?) I will consider it forfeit.