If he wants a hammerless double rifle,and wants a big bore, he first needs to find a quality fairly new shotgun action to start with. The trouble is, most shotguns that are good enough to to make a double rifle from, are almost as expensive as a good used double rifle! Pritty is, not necessarily means "pritty does"! His likeing of the old LC Smiths is an example. It is almost the weakest shotgun action made,that is more expensive than a Savage 311! A real good action is the Browning BSS action. It will take a lot of cartridge, but they are getting hard to find. Someone speaking of the RIGBY being made on Merkel shotgun actions. This is not true, they both are being made on Anson& Deeley rifle actions. Merkel shotguns are made on rifle actions. This is not a draw back, every gun maker in England uses actions made by someone else. Most are A&D, and Webbley actions. Many of them use barreled actions made in Germany, and finish them, and engrave their name on them. The only makers I know of who make their own actions are B.Searcy, and most of the German, and Belgian makers.