The Smith & Wesson Model 57 is a large frame, six-shot, double-action revolver with a 6 round cylinder, chambered for the .41 Magnum cartridge, and manufactured by Smith & Wesson. The Model 57 was designed to compete in both the Law enforcement and hunting firearms markets.
In the early 1960s, Elmer Keith, Bill Jordan, and Skeeter Skelton, all noted firearms authorities and authors, lobbied Remington Arms and Smith & Wesson to introduce a new .41 caliber police cartridge with the objective of filling a perceived ballistic performance gap between the .357 and .44 Magnums, and creating a chambering which they believed would be the ultimate for law enforcement purposes. In April of 1964 Remington responded by introducing the .41 Magnum cartridge, and in concert, Smith and Wesson launched the Model 57 revolver chambered for the new ammunition. Elmer Keith originally proposed the moniker “.41 Police” for the new cartridge, but Remington instead chose to call it the .41 Magnum, hoping to capitalize on the notoriety and popularity of its earlier Magnum offerings.
The first police dept to take the .41 mag as a service pistol was the Amarillo Police Department. Once again there is a picture with my pictures.
First introduced in April of 1964, the Model 57 was produced with 4”, 6”, 6-1/2", and 8-3/8” barrels in both highly polished blued and nickel-plated finishes. Using the S&W large "N" frame, the Model 57 was one of the companies’ premier products, offering superb fit and finish, basically the same pistol as the famous S&W Model 29, except in .41 instead of .44 caliber. Like the Model 29, the 57 sported a red insert front sight with a white outline adjustable rear iron open sight, as well as a target trigger, target hammer, and oversized wooden target grips.
Remington originally offered two ammunition loadings in its .41 Magnum cartridge lineup. The first was a full-power 1300-1400 ft/s hunting or heavy-usage jacketed hollow-point bullet which rivaled the stopping power of the mighty .44 magnum while boasting less recoil and a flatter bullet trajectory. The second loading was a less powerful 1,150 ft/s 210 grain lead semiwadcutter intended for law enforcement usage. 
Due to a number of factors the Model 57 unfortunately never became the “next great police loading” that its developers and supporters envisioned. First, the majority of departments and rank and file officers were perfectly content with their traditional .38 Special revolvers, and if more stopping power was needed, cartridges such as the popular .357 Magnum were available. In addition, when senior peace officer officials could be convinced to evaluate the .41 Magnum, many complained that even the lighter .41 magnum “Police load” was unpleasant to fire, while the .357 Magnum offered adequate performance without the bruising recoil and muzzle blast associated with the .41. Also, the marketing decision by S&W and Remington to dub the cartridge a “Magnum” ended up working against them in their desire to address the law enforcement market. Police organizations found the connotation of a hi-powered “Magnum” hunting-type weapon to be unpalatable in an era when they were struggling with political correctness and pursued positive public relations to offset any possible public perception of police brutality. Although the .41 Magnum was adopted as a police departmental standard by a few cities such as Amarillo and San Antonio Tx, most chose to pass. In addition, after the introduction of the successful .44 Magnum Model 29, and the fame garnered due to its use by Clint Eastwood in the film Dirty Harry, other large caliber and Magnum revolvers, including the .41, somewhat fell out of favor with the general public and American firearms market. Finally, a series of hugely popular and successful lighter and smaller-framed revolvers crafted from stainless steel emerged in the mid 1980s. These police-issue oriented firearms, exemplified by models such as the S&W Model 66, accelerated the Model 57’s demise. Overall, the Model 57 and its variants failed to generate the interest (or sales) which had been hoped for.
Smith & Wesson Model 58
On July 10 1964, S&W introduced a more basic and inexpensive .41 Magnum intended for procurement by police departments. This budget version of the Model 57 was similar in principal of design to the .38 Special S&W heavy-barrel Model 10, or .357 Magnum Model 28 Highway Patrolman. Weighing in at 41 ounces, the Model 58 featured a 4” barrel, fixed iron open sights, and simpler standard “magna service” grips. Finish options were the same as its upscale Model 57 brethren, blued and nickel, but shortly after the Model 58’s introduction S&W decided a less expensive “matte” bluing treatment would be more appropriate for the basic “workingman” model. The no-frills Model 58 also lacked an ejection rod shroud, but retained the pinned barrel and counter bored cylinder of the more expensive Model 57. The Model 58 was manufactured from 1964 to 1977 and roughly 20,000 were produced.
Smith & Wesson Model 657
No longer in production, the S&W Model 657 was basically a stainless steel version of the standard blued carbon steel Model 57, available with identical features and in the same barrel lengths.
Smith & Wesson Model 57-5 Mountain gun
A semi-custom version of the standard Model 57, the Model 57-5 “Mountain gun” has been marketed at various times by Smith and Wesson. In 2006 the Mountain gun was listed in the S&W catalog as available with a 4” tapered barrel, rounded frame, custom wood finger groove grips, adjustable iron sights. It was also factory drilled and tapped for the mounting of telescopic hunting sights.
Smith & Wesson Model 357PD
Similar to the "Mountain Gun" and also listed in the S&W 2006 catalog, the the 357PD was offered with a dull finish black 4” stainless steel barrel, titanium cylinder, a red dot front sight and adjustable rear, and also included wood finger groove grips. It weighted a scant 27.5 oz and was marketed as an ideal backcountry/hiker's carry pistol.