WHAT DOES FO FRONT MEAN?

† NOTE: The receiver-mounted, Picatinny-style rail is built to support most optics and optic mounts meant to be used with Picatinny/ MIL-STD 1913 rails. Having said that, on account of lessened clearance between the highest in the receiver and The underside with the optics rail, optics and optic mounts that stretch over .This is an more mature th