The M2HB-QCB Machine Gun is a recoil operated, air-cooled, disintegrating link belt-fed machine gun, capable of both sustained automatic and accurate single shot fire. The Quick Change Barrel (QCB) feature allows the operator to change the barrel in a fraction of the time required by the standard M2HB and eliminates the error inherent in headspace adjustment. Only the QCB designed system allows for the interchangeability and use of the standard M2HB barrel. Although the quick change feature of the system is aborted, the advantage is the ability to use conventional barrels to maintain the availability of the system.