Newman's rifle had been sometimes misidentified as an.1876, but it is actually an 1873. I've looked at some scenes frame by frame and confirmed it.
I agree--an excellent movie, based on a good book. The movie follows the book very closely, although they of course had to shave it down to fit it into the viewing time. They also changed a few supporting characters, but the main story is very close. That means that if you like the movie, the book enhances your enjoyment by fleshing out characters and giving some background to the events in the movie.
CC Griff