The Del-Ton complete upper receiver assembly features a flat top upper receiver with a 16" M4 profile FNH hammer-forged barrel with double chrome lining. The 5.56x45mm NATO chamber, 1 in 7" twist, and M4 feed ramps ensure reliability with a wide variety of commercial and surplus ammunition. The M4 upper features a carbine length gas system and sight radius. The barrel is threaded 1/2"-28 with an A2 flash hider. Steel parts are finished with a phosphate coating; the aluminum upper is hard-coat anodized. The Extreme Duty Upper utilizes a Cold Hammer Forged Barrel made by FNH but since they are made specifically for Del-Ton, there is no FNH stamp found on the barrel. Customers can verify their barrel is an FNH barrel by looking for a stamp that says "MP" meaning Magnetic Particle Inspection.
Installation of AR-15 upper assemblies with certain features including, but not limited to: flash hiders, bayonet lugs, and threaded muzzles may violate state and/or local laws.