Farrell products are milled from solid bar stock with all work performed in the U.S.A. factory. While most manufacturers build a thinner rail that requires taller rings, we use a thicker dimension on our rails and lower ring heights that allow more room for porting the underside to eliminate shell ejection issues which provides a rigid platform for your scope to perform at its maximum ability. We also control the depth of the screw with a countersink and do not recommend Loctite to hold it in place. Each rail includes T15 Torx head screws. Use 20 to 25 inch lbs. to install.