It was first seen when John McClane was forced to wear a racist sign in Harlem. After a mob began harassing him, Zeus Carver decided to help by grabbing a nickel-plated Smith and Wesson Model 36 with Pachmayr grips that was duct-taped to McClane's back. Zeus fended off the mob and likely saved John's life.
Another Smith & Wesson Model 36 was seen at the end of the film. For some reason, it was not the revolver that was earlier seen in Harlem, but a standard issue revolver of the same make and model. Zeus and John were overseeing the operation to stop Simon Gruber and his men from the helicopter in Quebec, they we're fired upon by Simon from another helicopter with his M60 Machine Gun. McClane asked the helicopter for a gun and wasn't too thrilled that he got a Smith & Wesson Model 36 revolver. After firing four shots at Simon's helicopter, Simon fired back and damages the helicopter that McClane and Zeus are on. After the pilot was forced to land the chopper, McClane exits the chopper and has Simon chase him away from Zeus.
After ducking behind the car, he sees he only has two bullets left on the Smith & Wesson revolver. As McClane tries to get a good shot at Simon, the helicopter corners him. As Simon looks at McClane at the eye and prepares to finish him once and for all, McClane sees the chopper is above the electrical line. As he aims for it, he says to Simon, "Say hello to your brother." Then he fired the last two shots of the Smith & Wesson revolver to the line. Then the electrical line falls on the helicopter's main rotor and destroys it, killing Simon and Katya. After seeing the wreckage of the helicopter, McClane says to the fallen Simon, "Yippee Ki Yay, Motherfucker" as he at last killed his enemy.