Are you for real? Gunsmith will do nothing to restore the value of the unfired gun. Buyer made the choice of firing the revolver and lowering its value.If he has wrecked the value with use, then it is fair to assist with getting the gunsmith to service it
Idiot kept firing the revolver after it had problems. Lowering its value even more.
That's stupid tax. He broke the gun, he fixes it.