Watto:

Sounds like a really neat gun.

Cape guns with two similar bored shotgun barrels {one rifled, one smooth} used to be fairly common is Sweden. Some possessed straight rifling. I believe the most common bore was 20. I can't remember the Swedish term for the guns but they were indeed very handy and practical guns. There were special ball loads for the rifled barrels.

I'm sure others on the Swedish gunboards forum could clue you in much better, but the bottom line is that once upon a time {late-1800's-early-1900's} the advantages of guns like yours were better appreciated than they are now.

In the USA, some states actually ban the hunting of more than one type or class of game at a time {small game and deer for example} but nevertheless I am at times dumbfounded as to why combo guns are not wildly popular. My hunch is that Americans have been brainwashed into believing that only the bolt or lever are adequate tools for deer or big game harvesting, and thus they miss the possibilities available with a combo gun.

I am waiting for some enterprising gun company with a freethinking engineering department {PAY ATTENTION, RUGER!!} to design a readily regulatable double and combo system. One of Ruger's o/u shotgun models with a windage/elevation device and simple {"with gun included"} instructions for use just might sell. In the meantime, you have a really neat gun!

I guess I will have to wait for a Ruger 7x57R/12 gauge to hit the market...