M77 and M77 MKII WEIG-A-TINNYA(R) Style Scope Mount-Our Newest Scope Mount in the Ruger Rifle line. This mount converts the Ruger scope ring attaching points to a WEIG-A-TINNYA(R) Picatinny Weaver style mounting point. To determine if your rifle is the short action you need to measure from the center of the rear scope ring slot on the top of the receiver to the center of the front scope ring slot. The short action is 4" long, larger readings are the long action. Mfg: Weigand Combat