<P> During the late 1920s, and in response to demands for a more effective law enforcement version of the cartridge, a new standard - velocity loading for the . 38 Special was developed by Western Cartridge Company . This . 38 Special variant incorporated a 200 grains (13 g) round - nosed lead' Lubaloy' bullet, the . 38 Super Police . Remington - Peters also introduced a similar loading . Testing revealed that the longer, heavier 200 grains (13 g). 357 - calibre bullet fired at low velocity tended to' keyhole' or tumble upon impact, providing more shock effect against unprotected personnel . At the same time, authorities in Great Britain, who had decided to adopt the . 38 caliber revolver as a replacement for their existing . 455 service cartridge, also tested the same 200 grains (13.0 g) bullet in the smaller . 38 S&W cartridge . This cartridge was called the . 38 S&W Super Police or the . 38 / 200 . Britain would later adopt the . 38 / 200 as its standard military handgun cartridge . </P> <P> In 1930, Smith & Wesson introduced a large frame . 38 Special revolver with a 5 - inch barrel and fixed sights intended for police use, the Smith & Wesson . 38 / 44 Heavy Duty . The following year, a new high - power loading called the . 38 Special Hi - Speed with a 158 grains (10.2 g) metal - tip bullet was developed for these revolvers in response to requests from law enforcement agencies for a handgun bullet that could penetrate auto bodies and body armor . That same year, Colt Firearms announced that their Colt Official Police would also handle' high - speed' . 38 Special loadings . The . 38 / 44 high - speed cartridge came in three bullet weights: 158 grains (10.2 g), 150 and 110 grains (9.7 and 7.1 g), with either coated lead or steel jacket, metal - piercing bullets . The media attention gathered by the . 38 / 44 and its ammunition eventually led Smith & Wesson to develop a completely new cartridge with a longer case length in 1934--this was the . 357 Magnum . </P> <P> During World War II, some U.S. aircrew (primarily Navy and Marine Corps) were issued . 38 Special S&W Victory revolvers as sidearms in the event of a forced landing . In May 1943, a new . 38 Special cartridge with a 158 grains (10.2 g), full - steel - jacketed, copper flash - coated bullet meeting the requirements of the rules of land warfare was developed at Springfield Armory and adopted for the Smith & Wesson revolvers . The new military . 38 Special loading propelled its 158 grains (10.2 g) bullet at a standard 850 ft / s (260 m / s) from a 4 - inch (100 mm) revolver barrel . During the war, many U.S. naval and marine aircrew were also issued red - tipped . 38 Special tracer rounds using either a 120 or 158 gr (7.8 or 10.2 g) bullet for emergency signaling purposes . </P> <P> In 1956, the U.S. Air Force adopted the Cartridge, Caliber . 38, Ball M41, a military variant of the . 38 Special cartridge designed to conform to the rules of land warfare . The original . 38 M41 ball cartridge used a 130 - grain full - metal - jacketed bullet, and was loaded to an average pressure of only 13,000 pounds per square inch (90 MPa), giving a muzzle velocity of approximately 725 ft / s (221 m / s) from a 4 - inch (100 mm) barrel . This ammunition was intended to prolong the life of S&W M12 and Colt Aircrewman revolvers equipped with aluminum cylinders and frames, which were prone to stress fractures when fired with standard . 38 ammunition . By 1961, a slightly revised M41 . 38 cartridge specification known as the Cartridge, Caliber . 38 Ball, Special, M41 had been adopted for U.S. armed forces using . 38 Special caliber handguns . The new M41 Special cartridge used a 130 - grain FMJ bullet loaded to a maximum allowable pressure of 16,000 psi (110,000 kPa) for a velocity of approximately 950 ft / s (290 m / s) in a solid 6 - inch (150 mm) test barrel, and about 750 ft / s (230 m / s) from a 4 - inch (100 mm) revolver barrel . The M41 ball cartridge was first used in . 38 revolvers carried by USAF aircrew and Strategic Air Command security police, and by 1961 was in use by the U.S. Army for security police, dog handlers, and other personnel equipped with . 38 Special caliber revolvers . A variant of the standard M41 cartridge with a semi-pointed, unjacketed lead bullet was later adopted for CONUS (Continental United States) police and security personnel . At the same time, . 38 tracer cartridges were reintroduced by the US Navy, Marines, and Air Force to provide a means of emergency signaling by downed aircrew . Tracer cartridges in . 38 Special caliber of different colors were issued, generally as part of a standard aircrew survival vest kit . </P>

What's the difference between a 38 and 38 special