Andro Corp Industries Barrel 5.56 NATO 16 inch Medium Contour Mid-Gas 1-7 Twist 1/2x28 Thread Black Black. This unit is specifically designed to be ran in conjunction with a silencer.We do not guarantee reliable cycling with some manufactures ammunition without the addition of a silencer. Specifications for Andro Corp Industries AR-15 5.56 NATO Threaded Barrel: Manufacturer: Andro Corp Industries Color: Black Finish: QPQ Corrosion Resistant Fabric/Material: 4150 CMV Melonite Caliber: 5.56x45mm NATO Barrel Profile: M4 Gas Block Journal Size-Diameter: .750 in Threads per Inch: 1/2x28 Barrel Twist Rate: 1-7 Barrel Material: 4150 Chrome Moly Vanadium Flutes: No Gun Make: AR Platform Gun Model: AR-15 Condition: New Gas Block Journal Size-Length: .078 in Country of Origin: USA Features of Andro Corp Industries AR-15 5.56 NATO Threaded Barrel 4150 CMV Melonite .070 Gas Port Size QPQ M4 Feed Ramps Extension Carbine Gas Package Contents: Andro Corp Industries AR-15 5.56 NATO Threaded Barrel What firearm models does the manufacturer say Andro Corp Industries AR-15 5.56 NATO Threaded Barrel is compatible with? The manufacturer suggests that Andro Corp Industries AR-15 5.56 NATO Threaded Barrel is compatible with AR-15Andro Corp Industries B55616: Barrel 5.56 NATO 16 inch Medium Contour Mid-Gas 1-7 Twist 1/2x28 Thread Black Black