...Structure) is a "polylithic" upper receiver assembly, in which the upper receiver and handguard have This VIS upper accepts all standard AR15/M4 barrels. No proprietary barrel assemblies are A small number of these VIS units have cosmetic blemishes, small scratches, or different types of...May 05, 2020 · ALSO, if you’re shopping for the best AR-15 complete upper receiver because you work in law enforcement or are in a position where your life may depend on this purchase, you need to remember that a complete upper receiver assembly is a key component of your life-saving tool, not a vanity project. Read, seek out more info, and ask questions. Precision Rifle - 6.5 Creedmoor (Upper Assembly). Embed. Share. Rumble — In this video I assemble the upper receiver. Sign in and be the first to comment. ... and disable advertisements!