Cartridge conversions were fairly common, but smokeless powder caught on between 1890 and 1910.
So an authentic cartridge conversion would have still shot black powder. Although without all the rigamarole of loading the chambers. I think most of the scenes were outdoors in the movie.
I have shot more than my fair share of black powder, but have never handled a conversion. I suspect the cheap and easy conversion loaded by removing the cylinder and replacing it using the original mechanism. So it would still be easy to swap a live cylinder for a blank one.
Was it still common practice to grease the chambers with a conversion or did that fall out of style? How were spent cartridges removed from a conversion?
I have no idea how phony Hollywood is on these things. I would think OSHA would have them hamstrung on smoke and noise indoors, and out.. Louder reports could be added later. I just never see enough smoke in western movies to make me believe they’re shooting black powder. White smoke and lights would be a nightmare, I would think.
With no exposed powder, I don’t know why they’d grease the cylinder.
Having seen the photo of the armorer, I don’t know that I’d even trust her to maintain black powder weapons. I think they make every effort to make things easy, but clearly they are far from idiot-proof.
Conversions had an ejector rod added to them, similar to one on a SAA Colt.