I don’t remember much about this movie. Only a scene from ~ end of the movie where:

The traitors and slaves(black) were in a cage/carriage and the traitors managed to convince the bad guys to release them from the cage in exchange for a info(not sure what was the info, I think about where a guy is) and he managed to steal one of the bad guy’s gun and in the carriage there was some dynamite, eventually the “traitors” letting the slaves get away.