Great catch on that one Doc. What a deal! For the price you paid you practically stole it!
It probably isn't the trigger that's the problem because the ad only said the hammer wouldn't stay back at half cock. So I assume the hammer does stay back at full cock.
Since the same engagement point of the trigger catches both the half cock and full cock notch on the hammer, I would venture to say it isn't the trigger that's the problem. I suspect the half cock notch on the hammer is either worn down, or broken off. Such breakage which could happen if the revolver was at half cock and was dropped directly on the hammer breaking the half cock notch on the hammer.
Or else someone who didn't know what they were doing filed it down thinking to get a more sensitive trigger and accidentally mistook the half cock notch for the full cock notch, and filed it down too much. If any of those are the case, you should be able to fix it by just replacing the hammer.
Or if there is any half cock notch ledge left at all, you might be able to file the hammer so that you re-make the half cock notch deeper so it will work again. I'm sure you'll let us know what the problem is when you get it disassembled and figured out. I also know whatever the problem is, with your skills you'll figure it out and fix it.
Since it is rated at .44 mag pressures and has that long barrel, you can't overload nor hurt it by using full cartridge case charges of BP. I'd suggest loading up your .44 mag brass to full capacity with a BP load, bench rest it and see what kind of groups you get firing several cylinders that way, and then take it down slowly in 5 grain increments shooting several cylinders of each different loading until you get your best/closest grouping, and then stick with that load.
Looking forward to your post when you get it disassembled and evaluate the problem.
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