The 910 was the economy version of the 5904, 910S was the economy version of the 5903. Aluminum alloy receiver with a blued carbon steel (910) or stainless steel (910S) slide. What made them economy pistols was the barrel, which had only one locking lug instead of two, a lot less machining steps on the exterior of the slide and receiver, blued slides were not polished and the blue finish was thin and not particularly durable, and plastic was used for the sights, recoil spring guide rod and magazine catch.
One might think that all these cost cutting measures would result in a pistol that was less reliable, but the economy pistols were just as reliable as the full-featured pistols. These economy class S&W's were designed to compete with Glock for law enforcement and self-defense markets. These days, finding one that is NIB, with documents, for $300 is exceptionally rare.
