Ruger Mark IV, Target, Single Action, Semi-automatic, Metal Frame Pistol, 22LR, 10 Bull Barrel, Aluminum, Blued Finish, Checkered Synthetic Grips, Adjustable Rear Sight, Ambidextrous Safety, 10 Rounds, 2 Magazines 40173 The Ruger Mark IV Rimfire Pistol features a simple, one-button takedown for quick and easy field-stripping and proper chamber-to-muzzle cleaning. Pressing a button in the back of the frame allows the barrel-receiver assembly to tilt up and off the grip frame without the use of tools. Cold hammer-forged barrel results in ultra-precise rifling that provides exceptional accuracy and longevity.