At the film's beginning, Andy Dufresne (Tim Robbins) is seen loading a Colt Detective Special while in a drunken state. During the trial for killing his cheating wife and her lover, he says he didn't do it, but threw the gun in the river, ruining his chance of proving his gun didn't commit the crime.
The attorney that questions Dufresne shows the jury a revolver for props effect, which is a Colt Police Positive in .38 caliber. Red (Morgan Freeman) also sees a Colt Police Positive in a pawn shop window.
Captain Hadley (Clancy Brown) uses an M14 Rifle fitted with a scope when Tommy (Gil Bellows) tries to tell the prison warden that he knew the man who really killed Dufresne's wife and lover. It is not likely an M21, since prisons aren't usually outfitted with Marine sniper weaponry. Since at the time this scene takes place, the M14 and M21 rifles were in frontline service with the U.S. Military, it is doubtful they would be issued to guards in some prison in New England.
In any event, close inspection of the rifle also reveals that it lacks the U.S.G.I. M-14's trademark, the fire control selector lug.
Warden Norton (Bob Gunton) pulls a Smith & Wesson Model 10 revolver with a 2" barrel from his desk when the police try to break into his office to arrest him for tax fraud and murder. He loads up the gun with the intention of fighting them.
