Volquartsen Competition Bolt for Ruger Mk II, Mk III, or Mk IV A Volquartsen Competition Bolt improves the reliability and functionality of your Ruger Mk II, Mk III, or Mk IV Pistol. The most obvious feature is the extended gripping knob at the rear of the bolt... It's much easier to grasp than the factory bolt. Also incorporated into this bolt are an Exact Edge Extractor and a SureStrike Firing Pin... These two parts will eliminate stovepipes and misfires. And like all Volquartsen premium parts, the machining and assembly of these bolts are held to closer fitting tolerances than factory mass production parts. Mk II Bolt vs Mk III Bolt - They're identical in function except the Mk III has an actuator for the Loaded Chamber Indicator. If you have removed the LCI or just don't have one (Paclite or LLV barrel for example), use the Mk II bolt.