Miller,
I have played this game, with my own R10, in a safe area, with live ammunition. It is possible to get a Darne R model to fire with the opening lever out of battery. I've done it. My own Halifax copy acts much like yours, and like my R10, there is a point just prior to the action being completely closed that you can get the sears to trip, and fire the gun, assuming live ammunition is chambered. The R10 I own has been fired many, many thousands of times, during my ownership and that of others before me, and is not as tight as the old Halifax, which shows no signs of use at all. If I had a stuck, live cartridge, in any double gun, I'd figure out a way to get it out that didn't involve activating the ejector mechanism, with the triggers, but, maybe, that is just me. It is true, in the pre-war directions for Darne R model guns, this method is mentioned, but, I've never seen it mentioned in post war directions for the guns. I'm guessing someone, somewhere, discovered the hard way, with disasterous results, what I learned when I experimented with my R10, and the company quit promoting that feature, if that is what we want to call it. As I have pointed out, a Charlin will not fire until the lever is completely closed.
As I have posted prior, I do consider it to be a fools errand. I never recommend it.
Best,
Ted
