I am planning a similar project in the not to distant future myself. However I want to use a Ruger Gold Label frame and make it in a British Caliber (not sure which one yet), and I am also flexable on the frame too I would just like to use the ruger. I ordered the book "building double rifles on shotgun actions" by an author named Brown. Any good sources of info or tips you could provide would be greatly appreciated thanks. Cant wait to see the pics!