The main weapon the USPF issues to Snake Plissken (Kurt Russell) is a MAC-10 fitted with a sound suppressor and a scope mounted on the silencer. After Snake is captured, the Duke of New York (Isaac Hayes) uses it for the remainder of the film, notably using it to shoot at, but not kill the President in front of his gang. The Duke uses it single shot only and the Suppressor doesn't seem to silence the sound anymore at this point, guess it was supposed to be some futuristic barrel extension as it is larger than average, though its possible the silencer baffles have simply worn out.
Snake's sidearm in the film is a Smith & Wesson Model 67 with a scope mounted on it. During the climax, Maggie (Adrienne Barbeau) fires it at the Duke before she is run down by him. You can tell it's a Model 67 because it has adjustable sights but lacks the lug that protects the ejector rod like on the Smith & Wesson Model 66. Therefore it's a 38 Special revolver and not a .357 magnum. If it was a Smith & Wesson Model 65 it would not have adjustable sights. The Model 67 is the stainless steel counterpart of the Smith & Wesson Model 15 Combat Masterpiece.
The U.S. Police Force Soldiers throughout the film and U.S.S.S. Agents in the Air Force 1 hijack scene use slab side M16/AR-15 SP1 rifles with their hand guards removed and replaced with a slender plastic sleeve that wraps around the barrel and gas tube, in order to make them look more "futuristic". Some of the rifles have three prong flash hiders, and others have the A1 birdcage flash hider. The President (Donald Pleasence) in a freak rage is seen using one taken from a dead U.S.P.F. guard to kill the Duke of New York (Isaac Hayes).
