Colt 1911 45 acp 5 inch compensated barrel made by Roto 4M. Superb quality and high accuracy gun barrels. These barrels are made in the USA from the highest grade heat treated steel to precise tolerance using a special hammer forging process that results in very accurate barrels. This barrel exceeds Colt's specifications for standard barrels. This is a drop-in barrel for Colt 1911 guns. All other requires fitting.