When glassing a Ruger 77 I insert a straw in the front angled hole to keep the glass out of it. Don't use the frt. action screw while bedding it .Leave a small section of the flat behind the recoil shoulder to set the depth of the action, and use toothpicks to center the action in the stock. Use a guide screw in the rear hole to align it. I use a rubber jawed quick clamp over the front action ring to hold it down on the pad you left for a depth stop. Use only enough pressure to hold it in place. After the glass is set remove the straw and drill out the screw hole oversize so the screw dosen't touch on the sides. Remember to relieve the front, bottom, and sides of the recoil lug so only the rear face is in contact. Chisel out the flat pad of wood used as a depth stop.
That angled frt screw was a big mistake IMHO, but glassing is still possible and does help accuracy when done right. Their recoil lug is the reason they came out with the Express model for the .375 HH and bigger calibers. Ruger has said the regular one is not big enough to contain the thumpers.