THE BEST SIDE OF COLT M4 TROOPER 5.56MM 16"

This upper receiver traces its origins back some 6 years to guns Colt made for the SCAR (Exclusive Operations Forces Fight Assault Rifle) plan on the U.S. Distinctive Operations Command (SOCOM). It can be made to obviate the need for a independent various-rail handguard for mounting components, affording best alignment of components mounted in-line