To answer your interest, Pooch, one of those who copied the sliding breech was F. Soleilhac and one of his guns is now at auction on Naturabuy website at 890 euros. It has 65 mm (2-1/2 inch) chambers. If interested, and I can't recall the gauge, you'd want someone to inspect it for sure. Many others made the sliding breech, often using Darne-supplied barrels.
After acquiring SIFARM, Verney-Carron made two grades of Francisque Darne guns that figure in their early-mid 60s catalogues. V-C was the last of the many successors of F. Darne who had died in WWI.
You'll find photos and the American Rifleman article on the Belgian-made four-shot sliding breech in Geoffroy Gournet's website listed above. Just scroll down a ways as I posted it a year or two ago.
Ted is on track about stock geometry, the safety etc. I prefer my short-chamber 10-gauge Darne R-16 over the 12-gauge Charlin and the 16-gauge Francisque Darne largely because the safety is easier to use -- and I've had it restocked to fit me...
Regards, Tim
A Soleilhac seems to crop up ever so often. I had heard they were rather utilitarian. However utilitarian and 2 1/2 inch chambers suits me just fine, particularly so in a 16 ga.
