I presume it is a Hunter One-Trigger, works great when it works, a nightmare to work on when it doesn't. Sometimes it is a matter of tightening a screw or loosening a screw to make it work, or it might be one of those little springs. Dewey Vicnair would be a great choice, also our own Dr. Bill Hambige. Call both and see whomever you are closer to. Unfortunately it is a receiver so it has to go FFL or CRL. (kind of dumb)