SPECIFICATIONSCALIBER: 5.56x45mm NATO WEIGHT: 4.2 Lbs. OVERALL LENGTH: 21.25″ BARREL LENGTH: 7.25” HEIGHT: 5” WIDTH: 2.25” (Widest Points) BOLT: MIL-Spec, 8-Lug Rotating Bolt BARREL EXTENSION: MIL-Spec 8620 BARREL: 4150 Vanadium, Gas-Ferritic Nitrocarburized 5.56 NATO (1/7 RHT with ½-28 tpi Muzzle Threads) RECEIVERS: Multi-Caliber with Captive Push-pin Takedown Aerospace Grade 7075-T6 Forgings GRIP: High-Impact Synthetic Polymer (model shown) HANDGUARD: Aluminum alloy, Magpul M-Lok®  ALUMINUM FINISH: MIL-A-8625F Black Hardcoat Anodize STEEL FINISH: MIL-Spec Manganese Phosphate MAGAZINE: 10 rd. Detachable (Can accept any AR15/M16 Magazine)