The .38 Super or .38 Super Automatic (C.I.P. designation) is a pistol cartridge that fires a in ( mm) diameter bullet. The Super was introduced in the late 1920s as a higher pressure loading of the .38 ACP or .38 Auto. The old .38 ACP propelled a -grain ( g) bullet at ft/s ( m/s). The improved .38 Super Auto pushed the same -grain ( g) bullet at ft/s ( m/s). The .38 Super has gained distinction as the caliber of choice for many top pistol match competitors; it remains one of the dominant calibers in IPSC competition.