Magazine articles in the 1960's discussed these conversions and concluded that the only big problem was if you reloaded. The short .38 S&W chambers were lengthened to take the .38 spl cartridge. This caused a change in the chamber wall where the diameter transitioned from one ctg to the other. Fired cases show this bulge and made reloaders unhappy as fired .38 spl cases had to be fully resized, resulting in shorter case life. Cogswell and Harrison conversions are generally very nicely done.