What a treasure! The gun clearly gave your great grandfather, and grandfather, many days of joy afield. A $2000 - $4000 Turnbull or Dudley like new restoration will remove the evidence of your family's holding and using the gun. Be aware that any work done wrong will significantly diminish the value.
It does need to be refurbished, checked and cleaned internally by a qualified double gun specialist, and the recoil pad replaced with a period appropriate pad, hopefully to be returned to the field in a younger family member's hands.
I would suggest a research letter which might document your great grandfather as the original purchaser.
|