The RU-MK II and RU-R triggers are precision engineered for Ruger rifles, crafted from A-2 tool steel with investment casting, heat treatment and drawing to a Rockwell hardness of Rc 50-55 for durability. The radius ground sear surfaces reduce creep for a smoother trigger pull. These User-friendly triggers are easy to install without complex modifications. The RU-MK II fits Ruger M77 MKII rifles with a 3-position safety, while the RU-R replaces non-adjustable triggers in 77/22 and 77/17 rimfire rifles. Not compatible with V/T models with a 2-stage trigger, these triggers offer adjustable weight of pull and factory safety compatibility for a customizable shooting experience. Replacement trigger for existing Ruger bolt action centerfire rifles The kit is compatible with Ruger M77 and M77 mark II models The kit is compatible with the new "Hawkeye" models equipped with the LC6T trigger The kit is also compatible with the Ruger scout Operation for right or left hand use Includes comprehensive instructions, a hardware pack and a wrench to facilitate straightforward user installation Pull weight range - 14 oz - 2.5 lb