Dittos to that. I mean, if it is an older gun, the seller should understand that you want to see it. Contact him and let him know you are sending a "buyers agent". Let him know you are serious and not jerking him around. Assuming your rep knows what he's doing, ie check the bore, stock (for cracks and oil seepage), the rib, chambers (measure them with a shell if there is any chance it might be 2 1/2" etc ) and brings some snap caps to make sure it fires, it should reassure the guy, given that he's selling something solid. Failing that, ask for a ten day non-firing inspection. Tell him you'll pay shippng both ways plus $20 even if you send it back.
FQ13