.38 refers to the type of firearm and firearm cartridges. The .38 is considered a large dead space firearm cartridge; Anything larger than .32 is considered a large caliber, and one of the most common handguns manufactured in the United States. Prior to 1990, the standard sidearm of police in the United States was a revolver that fired the .38 special cartridge, seconded by the .357 Magnum revolver.