'A shotgun conversion merely for cost reasons is probably not a good plan. Unless a person already possesses good gunsmithing skills and experience and knowledge of double firearms, probably not the best route to end up owning a worthwhile double rifle."

Unless you just want to mess with a project, I'd scrape my pennies until I could buy a proper double, otherwise you'll never truly be satisfied. Of course that's Just my .02 for what it's worth.