.38 S&W [SEP] manufacturer
.38 S&amp;W
The .38 S&W (9×20mmR) is a revolver cartridge developed by Smith & Wesson in 1877. Versions of the cartridge were the standard revolver cartridges of the British military from 1922 until the 1960s. Though similar in name, it is not interchangeable with the later .38 Smith & Wesson Special due to a different case shape and slightly larger bullet diameter.
History.
The round was first introduced in 1877 for use in the S&W .38 Single Action. 
After World War I, the British military sought to
models were added to the lineup. Featuring six-round cylinders, the Security-Six series represented one of the first modern revolver designs to feature a hammer powered by a coil spring utilizing a transfer-bar firing system, and was chambered for a variety of centerfire ammunition cartridges including .38 Special and .357 Magnum, as well as .38 S&W and 9×19mm Parabellum (9mm Luger). All Security-Six series revolvers came with original equipment manufacturer (OEM) supplied service-style wooden grips. The wood grips were