Smith & Wesson Model 15
The Smith & Wesson Model 15 was a six shot double action revolver made by Smith & Wesson from 1949 to the late 20th century. Law enforcement agencies, including the San Francisco Police Department, used this weapon. 

Officers of the SFPD who were stationed in a security corridor at Mercy Hospital in 1986 were equipped with this weapon. ()

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 Weapons used in Star Trek IV: The Voyage Home
Hand-held weapons
Projectile weapons