WHAT DOES FO FRONT MEAN?

† NOTE: The receiver-mounted, Picatinny-fashion rail is designed to support most optics and optic mounts meant for use with Picatinny/ MIL-STD 1913 rails. Nevertheless, resulting from diminished clearance among the highest on the receiver and The underside of your optics rail, optics and optic mounts that stretch greater than .Ruger’s friction-