Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. The Ruger Mark III is a .22 long rifle semi-automatic pistol manufactured by Sturm, Ruger & Company. It is the successor to the Ruger MK II, and includes several new features. Addition of a visible loaded chamber indicator on the left side. Magazine release moved, from bottom of grip to behind triggerguard. All Mark III pistols with adjustable sights are drilled and tapped for a Weaver-style scope base which ships with the pistol. A new magazine disconnect prevents the pistol from being fired with the magazine removed from the pistol. An internal safety lock has been added. Using a key, the safety can be locked in the "safe" position. Shorter tapered bolt ears.