DoubleStar's 16" DS-4 Flattop Upper starts with their 5.56 chambered 16" DS-4 barrel made from 4140 chrome moly steel utilizing the carbine length gas system. This barrel is attached to their flattop upper with their double heat shield DS-4 handguards. The upper is fully assembled with charging handle and semi-auto bolt carrier group. All parts are completely made in the USA.

Specifcations and Features:
Caliber: 5.56x45 NATO
Twist Rate: 1:9 Right Hand
Barrel Length: 16"
Barrel Type: Heavy Barrel
Barrel Material: 4150 Steel
Barrel Features: Black Nitride Finish, M4 Feed Ramps
Gas System: Carbine
Upper Receiver Type: Flattop
Upper Receiver Material: Forged Aircraft 7075 T6 Aluminum
Upper Receiver Features: "T"-Marks, Brass Deflector, Forward Assist, M4 Feedramps
Upper Receiver Coating: Anodized to Mil-Spec
Sight / Gas Block: "F" Marked Front Sight
Muzzle Device: A1 Phantom Flash Hider
Handguard: DS4 Double Heat Shield Handguard
Includes Charging Handle and BCG
Made in the USA

Fits:

AR-15 lower receivers