*ca compliant model* this model uses the juggernaut tactical's hell fighter kit.This prevents the magazine from being released while the upper and lower are married together for normal operation.5.56x45 mm caliber 16 inch barrel with a 1:8 twist polymer carbon fiber infused buffer tube polymer carbon fiber infused lower reciever polymer upper with metal inserts nano saf-t-first trigger 15 inch m-lok rail 10rd mag flip-up sights ati sr-1 stock 6.0 lbsAction: Semi-AutoCaliber: 5.56x45mm NATOBarrel Length: 16"Capacity: 10+1Trigger: Nano CompositeSafety: Manual ThumbWeight: 6 lbsStock Description: ATI SR-1 DeluxeMuzzle: A2 Flash HiderReceiver Material: PolymerSights: Flip Up Front & RearTwist: 1:8"Barrel Length Range: 16" to 16.99"Weight Range: 6 lbs to 6.99 lbsHand: RightStock Finish Group: Black