Arizona,
It seems that many who own and regularly shoot rimless cartridge doubles have little to no problem with extraction.

The guys who make a lot of noise about the weakness of the system often seem to have little to no first hand experience of extraction failures, and have made their mind up and then "closed the book".

IMO the fact is that the flanged cases are better in doubles and with these extraction issues really don't exist, barring head seperation of course.

That doesn't mean that I've also closed the book on this subject and based on the experiences of others here, I would not be afraid to own and use a rimless chambered double.