Volquartsen VC4LLV-6 Competition Upper 6'' fits Ruger MKIV and MKIV 22/45- This replacement barrel ("upper") is a superb upgrade for your Ruger MK IV. It's extremely lightweight, well-balanced, and offers match grade accuracy. The Volquartsen system uses a Type III hard anodized machined aluminum receiver to reduce the weight. This receiver is then fitted with a stainless steel match grade barrel. The whole thing swaps onto your Ruger MKIV as easy as taking the barrel on and off. - As shown above, we offer the LLV-4 in three configurations for your Ruger Mark IV or Mark IV 22/45: Plain with threaded muzzle, Target Sights w/threaded muzzle, and Target Sights w/Compensator.