I'm not an expert and at this time don't own a Ruger 77 rifle, however this subject is talked about in the February 2007 issue of The American Rifleman magazine put out by the NRA. Starting on page 58 in the technical gunsmithing know how section probably sponsored by Midway is a review of the Wheeler Engineering FAT firearm accurizing torque wrench. Bryce M. Towsley, the author, of the article/advertizement talks about torquing various screws such as ring, mount, and action screws. He gives some standard torque values. Towsley adds that he surveyed several manufacturers and that Ruger provided the folllowing information for tightening their action screws.
"First, tighten the front bolt to 90 inch-pounds. Second tighten the back screw to 50 inch-pounds. Third, tighten the middle screw to 50 inch-pounds."
The article did not mention what model Ruger rifle, or if the stock was wood, synthetic, or laminated.
You might want to find a copy of the magazine and read the article.