The .38 Smith & Wesson Special was born in 1898 and was an attempt to improve upon the .38 Colt which was the US service cartridge at that time and had proven itself ineffective in the Philippines. The first .38 Specials were loaded with black powder. In 1899, Smith chambered their new Military & Police revolver, later to evolve into the famous model 10, for the 38 Special. Sometime after WW1, when it became obvious that the military was going in a different direction with the 45ACP, Smith marketed the 38 Special as a police round and it began to gain favor with LE. The round of choice for police at this time was the 200 grain round nose at about 700 to 800fps. In a straight up gun fight, the round proved to be effective but didn't penetrate well against the primitive body armor of the day or when autos where involved. Late 20's, early 30's, they (Elmer Keith, Et. Al) began to experiment with high velocity rounds with lighter bullets in the 38. This led to the development of the N frame 38/44 around 1930 to stand up to the increased pressure of these early "+p" rounds. At this point, they had about maxed out the 38 without endangering people who were using the round in the M&P. In 1934, Elmer Keith, Phil Sharpe and Col. D. B. Wesson lengthened the .38 Special cases by 1/10th of an inch, used a 158 grain SWC bullet designed by Keith and Sharpe and drove it as fast as they could get it to go. This became the 357 Magnum and the premiere police round. It was the first cartridge to use "Magnum" in it's name. The N frame chambered for 357 would later become the Model 27. The 357 is still the round that all others are compared to when talking about stopping power in police rounds. I've spent a little bit of time on the street and police ranges and I think that the best police handgun ever is the model 66 loaded with 125 grain JHP's.