Not sure exactly what you are looking for. EGW and Murphy Precision both make picatinny rails for the Ruger 77 Mark II/Hawkeye. The receiver would need to be drilled and tapped to use them, of course.
Thanks for the info. Was hoping for a picatinny style that clamped onto the existing Ruger receiver. Wish Ruger would just bring out a round top receiver that took standard scope bases.