Marrakai, The chances of my ever seeing, let alone examining, a Greener's Treble Wedge-Fast are from slim to none. Where I live, I am lucky to even see a quality double barrel unless it is one I have bought and imported into Iowa from the outside world. I guess my points about the Greener crossbolt were either poorly stated or misunderstood. I don't feel at all that the Greener crossbolt is not a necassary or very useful item to have on your gun. I'm just saying that in most cases, where a cheaper double is purchased with the idea on converting it to a double rifle, I would be very surprised if the Greener made any contact at all with the rib extension, and I would worry too much about it if it didn't. The one gun that I can think of that might be bought relatively cheaply and converted would be an older Merkel. That being said, I would Never consider converting a Merkel that was still in good enough shape to use as a shotgun. It would have to have bad barrels or something else seriously wrong with it before I would even think about chopping it.
I'll bet that there will be some people who do cut up a good Merkel to make a rifle ,who will kick themselves later when they think back to what they did to their nice shotgun. There are plenty of damaged guns out there that could be used without cutting up a nice shotgun. I see lots of guys are thinking about chopping Huglu's to make double rifles. I wouldn't do that even to a Huglu, but if you have to cut a good gun, then it is better to use a Huglu than a nice Merkel!