I recently picked up a single shot bolt action Dreyse sporting rifle (octagon barrel, double set triggers, light engraving) and I’m trying to determine what cartridge it is chambered for. The bore is .44, and I made a chamber casting. It’s a slightly bottlenecked case, with a second step at the mouth which I assume is for a paper patch. The gun is not proofed, which dates it to pre-1890, but it has no other useful markings.
These dimensions are all approximate; it was hard to judge when I was starting to squeeze the chamber cast with the calipers.
Any help identifying this cartridge would be much appreciated - thanks!