Originally Posted by LoboGunLeather

There are certainly differences in the chamber and bore dimensions of revolvers, even those made by the same company.

SAAMI specifications for the .38 S&W cartridge include a larger case diameter, shorter length than .38 Special, and differences in the rim. The .38 S&W is a transitional cartridge, first offered in black powder loadings for the hinged-frame top-break revolvers. Modern ammunition loaded with smokeless powder is intentionally kept at modest pressures in deference to the limited strength of many .38 S&W revolvers.

During the Lend-Lease years leading up to US involvement in WW2 Smith & Wesson made many thousands of the "Victory" model, essentially the Military & Police model revolver. Most of those went to British Commonwealth nations and were chambered for the .38 S&W cartridge (British designation is .38-200, using a 200-grain round-nose lead bullet).

During the 1960's or so quite a few of those revolvers were re-imported to the US, and many were rechambered for .38 Special ammunition. Quite a few reports of ruptured cases were noted, due to the larger diameter of the chambers, intended for the shorter and larger diameter .38 S&W cartridge, then reamed out to accept the longer .38 Special cartridge. Accuracy was also "iffy" with many, usually credited to a larger bore diameter commonly used for .38 S&W (around .360" if I remember correctly).

There is no real advantage to shooting .38 S&W cartridges in a .38 Special revolver, even when the revolver in question will accept these rounds. .38 S&W ammunition is produced in much smaller quantities than .38 Special for the US market, so it is typically priced much higher than .38 Special ammunition. Also, revolvers chambered for .38 S&W (other than collectable specimens) generally have much lower resale values than comparable .38 Special examples of the same type, due to US consumer preferences.

Although the .38 Special was originally developed by Smith & Wesson, the case was actually a lengthened version of the .38 Long Colt cartridge then in use by the US Army. It is interesting that S&W chose this course, rather than starting with their own proprietary .38 S&W case dimensions and lengthening that round.

.38 Special ammunition is available in a great variety of forms, suitable for anything from paper-punching to serious self-defense use. I think the US shooter would be far better served by a good .38 Special revolver than a .38 S&W for just about any purpose.

Best regards.