Spikes Tactical Barrel 5.56 - 11.5in Lightweight CHF w/M4 Extension Stripped. We only offer high quailty barrels so you can be confident that your rifle will be off to a good start with which ever barrel you decide on. Specifications for Spikes Tactical AR-15 5.56 LW Cold Hammer Forged Barrel: Manufacturer: Spikes Tactical Color: Black Caliber: 5.56x45mm NATO Barrel Length: 11.5 in Gas System Length: Carbine Length Threads per Inch: 1/2x28 Barrel Twist Rate: 1-7 Gun Model: M4 Condition: New Country of Origin: USA Features of Spikes Tactical AR-15 5.56 LW Cold Hammer Forged Barrel: M249 SAW Chrome Lined Spec DIN 21CrM0V511 Light Weight Profile 1/7 Twist Rate 1/2 X 28 Thread Pitch for Muzzle 5.56 Nato Chamber .625 Gas Block Seat M4 Feed Ramped Barrel Extension MilSpec Phosphate Coating Weight 1lb 2oz Package Contents: Spikes Tactical AR-15 5.56 LW Cold Hammer Forged Barrel What firearm models does the manufacturer say Spikes Tactical AR-15 5.56 LW Cold Hammer Forged Barrel is compatible with? The manufacturer suggests that Spikes Tactical AR-15 5.56 LW Cold Hammer Forged Barrel is compatible with M4Spikes Tactical SB51106-LW Cold Hammer Forged Barrel 5.56 11.5in