Precision Reflex PRi AR15 / M16 Flattop Riser 3 Hole Black 05-0064. The full 1913 rail is elevated .45in with an overall length of 6.375in with 1.375in of overhang. The riser weighs 4.3 ounces. Specifications for Precision Reflex PRi AR15 / M16 Flattop...