U.S.S.S. Agent Richard Chance (William Peterson) uses a snub-nosed Smith & Wesson Model 19 throughout the film. Later, after Chance is killed, Agent John Vukovich (John Pankow) uses Chance's gun to kill Rick Masters (Willem Dafoe). The U.S.S.S. issued this revolver before switching to semiauto pistols. Agent Jimmy Hart (Michael Greene) uses one when going to check out Masters' counterfeiting warehouse.
Smith & Wesson Model 15
Later in the movie, we see Petersen using a Smith & Wesson Model 15 revolver. This gun is also used by other U.S.S.S. agents in the movie, and by an airport police officer.
Colt Detective Special
John Pankow, in his role of another U.S.S.S. agent, carries a 2" barrel revolver that looks like a Colt Detective Special, although it is never seen close enough