Ok, so here's the final installment to this story. The reason I needed the screw size for Ruger scope rings was due to the fact that as I was intalling a Nikon scope on my .44 Redhawk, my finely ground 25 year old gunsmith screwdriver blew up and destroyed one of the screws. I will probably wind up drilling it out. I then spent two days looking for Torx screws, this morning I called Ruger and the lovely lady, with whom I spoke, is sending me enough Torx screws to replace them all on both my Redhawks. Can't beat that.