The Ruger MK III, introduced in 2004 and produced until 2016, was a third-generation update to the Ruger Standard series, eventually succeeded by the MK IV. The MK III retained the classic steel-barreled design, with barrels threaded into the receiver, making them non-removable without machining. This model featured a variety of configurations, including the Hunter, Competition, and Target variants. The Hunter model stands out with a stainless steel frame, available in barrel lengths of 4.5, 5.5, or 6.875", fluted bull barrels, fiber-optic front sight, and adjustable V-notch rear sights, combined with half-checkered cocobolo grips. The Competition model also boasts a stainless steel frame, featuring a 6.875" slab-sided bull barrel and thumb rest cocobolo grips for enhanced control. The Target model is offered in both stainless and blued finishes, with a 5.5" bull barrel, adjustable rear sights, and either black plastic or cocobolo grips, making it a versatile choice for precision shooting. Additionally, the MK III introduced several safety features, such as an internal and external keyed lock, a loaded chamber indicator, and a visible chamber indicator—the first of its kind in a .22 LR rimfire pistol. The MK III 22/45 lineup further diversified the series with a polymer frame that emulated the grip angle of the iconic M1911, appealing to users who preferred that familiar feel.