Years ago, I helped Steven Bodio order a Darne R11 slug gun in twelve gauge. Mr. Bodio was, at the time, traveling frequently between New Mexico and Mongolia, and didn't want to bring two fireams on these trips. The Bruchets were not interested in producing a bunch of R11 slug guns at the time, but, agreed to build one for me.
The gun was regulated with Federal slugs at 60 yards, and choked to throw IC and Modified patterns with fine birdshot. I don't know how the gun would have worked with shot heavier than about number 5s. Bear in mind, the barrels on this gun were not rifled-that process was used on shot dispersion guns (canons raye) BUT, not slug guns. They were not working with sabot technology at the time, and, truthfully, there wasn't much reason to consider it, with the results they got with regular, rifled slugs.
I'm not sure why, but, the gun went down the road, and, last I had heard, had been choke tubed by Brileys. It was the only slug gun I imported from France, and at the time, Demas was certainly capable of producing a regulated slug gun as well. Demas has since been sold to Verney Carron.
There is no importer for Darne guns, I would suggest you would be better served by looking at Verney Carron.
I would expect that the purchase of either a standard grade, regulated double rifle, or, regulated slug gun, from either firm, would eat up most of $30K. Perhaps much more in the case of a higher grade gun.
You can read about Mr. Bodio's slug gun in the Double Gun Journal article "21st Century Jungle Gun".
Best,
Ted
