The Security Six was Ruger's first attempt at a double action revolver. Using their familiar technique of heavy duty components, solid frame and six-shot cylinder the Security Six was investment cast. The Sixes were among the first to use Ruger's patented transfer bar mechanism, a type of safety mechanism to prevent the hammer striking a cartridge, unless the trigger being pulled.
All Security Six and its subsequent models were sold with a choice of fixed or adjustable sights. A medium frame is used and made from blued carbon steel, with stainless steel introduced from 1975. Wooden grips were sold initially, before the Service and Speed Six were sold with rubber Pachmayr grips with the Ruger emblem in silver embedded init from the 1980s.
Chambered to fire the .357 Magnum, and its predecessor the .38 Special. The majority were sold with adjustable open sights, with few sold with fixed sights. Barrel lengths avaliable were 2.75in, 4in and 6in, and also sold with a variety of grips. The Security Six was introduced from 1968.
Also known as the "Police Service Six", the Service Six was intended to be sold to law enforcement agencies. Due to some police agencies specifing the 9mm Parabellum cartridge, the Service Six was introduced with a patented sprung cylinder ring to engage with the 9mm round which was rimless. The same barrel lengths as offered for the Security Six were offered, along with a 2in varient.
The same barrels as the Security and Service Sixes, along with a unique (for the Sixes) compact round-butt grip and some models were chambered for the .38 S&W cartridge. The Speed Six was also sold to Commonwealth countries, such as India, unlike to previous models.
The Security Six was chambered for the .357 Magnum round upon its release. However with the release of the Service Six and the later Speed Six more calibers were introduced:
All rounds are shot from, as the name suggests, a six-shot cylinder.
The Security Six and the later Service Six were sold on the basis of use in police forces in the US. This lucrative market had yet to be tapped by Ruger. The Sixes became popular, adopted by many US Government agencies such as the Postal Service, Naturalization Agency and Boarder Patrol, as well as police departments across the US (many of whom demanded different calibers).
In terms of numbers built, between 1972 and 1988 a total 1.5million (approx) were produced, mainly sold in the US but with a significant number of exports. Demand for second hand Sixes remains as high as the orginal interest.
The Six series would be replaced by the Ruger GP-100 in terms of production.