The revolver that kills Senator Jordan and his daughter Jocelyn in the 1962 movie has been customized so it can use a suppressor.
It doesn't look like a Nagant M1895
: the only suppressible revolver that was widely available at the time of the movie, and indeed one of the only suppressible revolvers available even today. So maybe Raymond Shaw's handlers modified a different revolver to have similar features and gave that to him?