COLT UPPER RECEIVER FOR SALE FOR DUMMIES

It is actually made to work While using the removable rear sight, that has a flip-up aperture adjustable for windage and elevation. Elevation changes are made By means of a drum calibrated for M855 ammunition at ranges of 200 to 600 meters. The rear sight is low enough to not interfere with most eye-relief-dependent optics.Quoted: Over the ALG/Geis