Note: This barrel is less than 16 and is subject to all rules and regulations. Can only be attached to pistol lowers or registered SBRs. Know your local laws and regulations before purchase.This Lewis Machine & Tool 5.56 Barrel is a great option if you are looking to build a compact AR-15. It comes with an A2 front sight gas block already installed and a delta ring attachment for two-piece handguards. At 14.5" in length, this LMT barrel has a carbine length gas system and a 1/7 twist rate. The bore is chrome lined for long lasting durability and the outside diameter is Phosphated. Threaded 1/2x28, the government profile will pair nicely with an A2 birdcage flash hider. The LMT 5.56 M4 barrel is built to high standards, so you can be sure you are getting a quality component.Features: 14.5" chambered in 5.56 NATO M4 profile 1/7 twist rate A2 front sight gas block (front sight post not included) Chrome lined bore 1/2x28 thread pitch Delta ring for two piece handguards M4 feed ramp extensionLewis Machine and Tool Company has been providing US Military, law enforcement, and government agencies with high-quality weapon systems since 1980. LMT is dedicated to providing that same level of precision engineering to civilians as well and is even expanding into foreign military services. All LMT Defense products are 100% made in America and they are a qualified 2005 GSA supplier. Lewis Machine & Tool has also won many awards for their quality engineering and excellence in business.