When the M16A2 was adopted in ... arrangement and the benefits of a lower optic mount lead the Army and Colt to collaborate on a “flat-top” upper receiver that could mount an infantry day ...

Inside the lower receiver at the rear a spring-loaded pin ... front sight and a removable windage- and elevation-adjustable M16A2-type carry-handle rear sight. The upper receiver also has standard ...

When the M16A2 was adopted in ... arrangement and the benefits of a lower optic mount lead the Army and Colt to collaborate on a “flat-top” upper receiver that could mount an infantry day ...