"Brownells ~ BRN-180 ~ Chambered in 5.56x45 mm NATO. Is a semi-auto short stroke gas piston Armalite pattern modern sporting carbine. Features a 16"" barrel with a 1/2x28"" threaded muzzle bearing an affixed three prong flash hider. Firearm has an overall black finish, side folding stock, and a free float aluminum handguard bearing M-Lok slots for attaching accessories. Comes with a single 30 + 1 capacity magazine."