I bought a barrel today , its a 30 herrett stainless steel. From the beggining of the chamber to the crown is 14 inches , then there is a peice added on that is 4 1/8 inches long with a muzzle tamer for a total of 18 1/8 inches . if The added on peice is threaded it is tight enough you cant get off without damageing everything . The question is , Is this a carbine barrel or pistol barrel ?