Luth-AR's .223 Mil-Spec Carbine Buffer Tube Complete Assembly Kit for AR rifles includes recoil buffer components for a new .223 AR-15 Carbine build or to convert your current AR-15 to use Mil-Spec carbine buffer tube recoil system. Features: For AR-15 rifles Kit includes Mil-Spec carbine tube, .308 buffer spring, .308 buffer body, latch plate and lock ring