A predecessor to the .357
Magnum, the .38
Smith and Wesson Special (actual diameter .357 inch) was introduced back in 1902. It is a
rimmed cartridge as was common in those days of
wheel guns.
It is a low pressure cartridge which is why it is quite easy to build a gun which can safely fire it. This is one reason that most paltiks in the Philippines are chambered for .38 Special. It is also the weapon of choice of security agencies in the Philippines as it is a cheap yet effective firearm.
Today, with the modern materials and manufacturing techniques, the .38 Special now comes in souped up versions, called +P or even +P+ rated, these higher pressure rounds still have the exact same dimensions but are capable of achieving much higher velocities, close to but not exactly magnum level velocities. +P rated .38 Special ammunition should only be fired in .38 Special guns that are rated for it or in .357 Magnum revolvers.
Since the .38 Special was only meant to be fired from revolvers which because of their design do not have the requirement of generating enough energy to operate a semi automatic action there also are very low pressure rounds available for this cartridge, some having a plastic casing and rubber bullets which only are propelled by the detonation of the primer.
Being relatively mild, this very versatile cartridge is a good place to start in learning to shoot a handgun once one has went past the .22 stage.
Also a decent defensive round in its own right the .38 Special will be with us for another hundred years and beyond.