Volquartsen Firearms Heavy Pistol Recoil Spring Ruger MKII MKIII MK IV and 22/45. This Pistol Spring from Volquartsen Firearms was specifically designed only for use with the recoil rod packaged in our kit. Compatible with .22/.45 caliber firearms the Volquartsen Recoil Spring is sure to provide you with years of impressive use. For a great way to make sure you are using some of the best that the shooting industry has to offer choose the Volquartsen Heavy Pistol Recoil Spring Ruger MKII MKIII MK IV 22/45. Specifications for Volquartsen Firearms Heavy Pistol Recoil Spring Ruger MKII MKIII MK IV 22/45: Manufacturer: Volquartsen Firearms Model: Heavy Recoil Spring Gun Make: Ruger Gun Model: Ruger Mark IV Ruger Mark III Ruger Mark II Caliber: .22 Long Rifle Country of Origin: USA Features of Volquartsen Firearms Heavy Pistol Recoil Spring Ruger MKII MKIII MK IV 22/45 This spring is designed only for use with the recoil rod packaged in our kit Package Contents: Volquartsen Firearms Heavy Pistol Recoil Spring Ruger MKII MKIII MK IV 22/45 What firearm models does the manufacturer say Volquartsen Firearms Heavy Pistol Recoil Spring Ruger MKII MKIII MK IV 22/45 is compatible with? The manufacturer suggests that Volquartsen Firearms Heavy Pistol Recoil Spring Ruger MKII MKIII MK IV 22/45 is compatible with Ruger Mark II Ruger Mark III Ruger Mark IVVolquartsen Firearms VC3RSO-H: Heavy Pistol Recoil Spring Ruger MKII MKIII MK IV and 22/45