I have an underhammer it is complete kit in 36 caliber with everything including curly maple wood. Paid 580.00 plus shipping asking 500.00 shipped. 32" barrel length. Draw filed barrel and action. Needs final polishing if needed.
That looks like a Billinghurst! If it is, it is well worth finding the right person to repair that. All that cracked part does is hold the action to the barrel.