The Colt OEM Series offers a no-compromise solution for consumers and dealers to build and offer customized rifles based on the proven Colt M4 Platform. Handguards Buttstock Trigger Guard Magazine and Rear Sight have been omitted completely. The OEM2 is build with a Low Profile Gas Block and without Handguard Retaining Ring to allow for the use of most aftermarket free float handguards. Action: Gas Operated Semi-Auto Caliber: 556NATO Barrel Length: 16.1" Finish Color: Matte Grips Stock: Pistol Grip Capacity: N/A Sights: Flat Top/Low Profile Gas Block OAL: 32" Metal Finish: Black Muzzle: Muzzle Brake Barrel Description: Chrome-Lined Twist: 1:7" Barrel Length Range: 16.00" to 17.99" Purpose: Hunting/Target Series: Carbine Safety: Safety Selector Finish: Matte Black Stock: None Overall Length: 32 Features: No Furniture Model/ Ready to Customize