FSP and Ted,
Yes, the French Darne book has abundant illustrations of early Regis Darne pivoting breech guns, both back and sideways.

The extractor, unfortunately has relatively little leverage until the trigger is pulled. My R-16 in 10 gauge will not extract unfired Federal plastic rounds, neither my reloads nor early RST ammo. It will extract what I take are Remington unfired rounds. NOTE that the Federal hulls are snug and must be pushed into the chamber rather than dropping in.
Regards, Tim