I was overhauling my FWB300S and during the re-assembly, the bolt that holds the rear plug wouldn't thread in propertly. I emailed Joe Rhea and asked if he had any tricks for this. Within 5 minutes, he called me and offered to loan me a metric tap to chase the threads. I got it in the mail in two days. Joe is such a great guy and a mainstay for our airgun community. I can't thank him enough! Best wishes to you, Joe.