The cdi rifle features a gas impingement system.It has manual safety, 7075-t6 aluminum receiver with anodized finish, 4150 chrome moly vanadium barrel with vortex flash suppressor, and a 15" m-lok free-float with magpul m-lok hand stop handguard.Other features include magpul ctr carbine stock, moe pistol grip with storage compartment, and mbus pro metal front and rear sights.Action: Semi-AutoCaliber: 5.56x45mm NATOBarrel Length: 16"Capacity: 30+1Trigger: Mil-SpecSafety: Manual ThumbOal: 32.75"- 36.13"Weight: 6.95 lbsStock Description: Adjustable Magpul CTRMuzzle: Vortex Flash SuppressorReceiver Material: 7075-T6 AluminumSights: Magpul MBUS Pro Front & RearBarrel Description: 4150 Chrome Moly Vanadium Chrome-LinedTwist: 1:9"Barrel Length Range: 16" to 16.99"Weight Range: 6 lbs to 6.99 lbsHand: RightStock Finish Group: BlackMetal Finish Group: Blued/Black