The Redhawk was the first large-bore double-action revolver made by Ruger. It was designed by Harry Sefried, who previously worked for High Standard Manufacturing Company, where he designed the High Standard Sentinel revolver. The grip profile of the Sentinel was used on the "Six" line of Ruger .357 double-action revolvers, which included the Ruger Security-Six and its variants, the Service-Six and Speed-Six. These revolvers were produced from 1970 to 1988, and were unlike other double-action revolvers in that they used a one-piece frame, rather than a removable sideplate, which lent them superior strength. The Redhawk, introduced in 1980, was a scaled-up and improved version of the Security-Six, the target model, with a square butt grip, adjustable sights, and 5.5- and 7.5-inch barrel lengths. The Redhawk was available in blued or stainless steel, and was primarily used by handgun hunters. The Redhawk, designed for long-term use with the heaviest .44 Magnum loads, included a new latch at the crane, to firmly lock the cylinder at front and rear, a feature last seen in the Smith & Wesson's triple lock design, discontinued in 1915.