Howdy
The 357 Magnum cartridge was a continuation of the 38 Special cartridge called the 38/44 Heavy Duty. Also known as the 38/44 S&W Special. To quote Neal and Jinks, the Remington Arms Company and Elmer Keith developed this cartridge in 1930. It carried a 158 grain bullet and achieved a velocity of 1,175 fps, delivering 460 ft. lbs of energy. This was in comparison to the standard 38 Special loadings of the time that propelled the same 158 grain bullet at 870 fps, delivering 266 ft. lbs of energy. To further quote Neal and Jinks, "This cartridge was developed primarily for use by police against the bullet proof vests and bullet proof automobiles that criminals of the period had begun to use."
Note nothing is stated about penetrating an engine block. The idea was to penetrate bootleggers' car bodies that had been reinforced with armor plating. The revolvers that were used with this cartridge were the large N frame 38/44 Heavy Duty revolvers. Basically a large N frame revolver chambered for 38 Special. They were called 38/44 because they were built on the N frame, which was often used for 44 caliber revolvers. The large diameter cylinder of these revolvers provided the strength needed to resist the pressure developed by these cartridges. They were not recommended for standard K frame 38s.
This is a Smith and Wesson 38/44 Heavy Duty:
In 1931 a target version of this revolver with adjustable sights, called the 38/44 Outdoorsman, was also offered.
Like this.
The difficulty with this arrangement was that the 38/44 ammunition could be chambered in any standard 38 Special revolver. I don't have any statistics on how often this happened, but it was not recommended.
According to Roy Jinks in 125 years with Smith and Wesson, published in 1977, the history of the 357 Magnum cartridge began with Phil Sharpe. He had been communicating with the S&W factory through the 1930s, urging them to produce a special revolver that could handle pressures beyond standard 38 Special pressures. In 1934, Winchester developed the new cartridge. It developed 1,515 fps with a 158 grain bullet. The new cartridge was christened the 357 Magnum. It was contained in a cartridge case about 1/8" longer than a standard 38 Special cartridge, so it could not be chambered in a conventional 38 Special revolver. I have heard the Magnum appellation came about because Douglas Wesson was a wine aficionado. I cannot vouch for that.
The new revolver developed for the new cartridge was simply called The 357 Magnum. Built on the same N frame as the 38/44 Heavy Duty, it was a luxury item, with a great variety of barrel lengths and front sight styles available. Smith and Wesson began a special marketing campaign registering each revolver to its owner. These revolvers became known as the Registered Magnums. The 357 Magnum revolver sold for $60, which was $15 above the price of any other revolver that S&W made at the time. Don't forget, this was the height of the Great Depression. Because of the high price, S&W did not expect to have to produce a high volume of the new revolver. However they were swamped with orders, and had a difficult time keeping up. In time the Registered Magnum program was dropped, and the revolver was simply cataloged as The 357 Magnum. In 1957, when S&W went over to a numbering system to identify its revolvers, The 357 Magnum became the Model 27, with the Model 28 being the slightly less expensive version without the fancy finish and checkering on the top strap and barrel rib.
Everybody knows that the first Registered Magnum was shipped to J Edgar Hoover, but not everybody knows that the second one was sent to Phil Sharpe.
Anyway, that's what I have been able to find out about the original loading of the 357 Magnum cartridge.
1,515 fps with a 158 grain bullet.
I have no idea what current factory loadings are.