Yeah I read that book years ago but, as I recall, those guns were built on modern box lock actions not "who knows how old, who knows what metallurgy" actions.

I'd be happier with a Winchester M 21 action as a basis for a DR. If you had a 2 barrel set you could just reline one and still have a fine shotgun too for less money than a quality DR.

While I love my classic double shotguns, I can shoot my Sporting Clays Browning Cynergy much better. Wonder if the same thing would be true of an O/U rifle ?