I don't see this being a viable product.<p>1) For a machine shop owner, you can already build such a "multi-shot gun" yourself quite trivially. I have a setup in my barn where I can spot-weld seven rifles together along the length of the barrel. I then use a bunch of loops of baling wire that run from the triggers to the end of the stock so that I can fire the correct rifle without any awkwardness.<p>I haven't tried this with pistols but the general approach should be the same.<p>2) My system also has the benefit of me not being tied to one company's proprietary standard of "interchangeable" parts. If you buy a Colt, you're stuck buying Colt parts forever. With my system, I can weld together any guns I want.<p>3) It does not seem very "viral".