This proprietary design offers enhanced rigidity over the USGI product.  The increased rigidity limits barrel deflection which aids in consistency/accuracy.   Less flex also reduces premature damage, wear, and failure of bolt lugs from misalignment.   A gas expansion chamber is machined above the charging handle track, combined with dual vents machined at the rear (each side, above charging handle latch) help to redirect and vent gas away the shooters face. 

This process of manufacturing barrels has been used for European small arms for generations, and it is gaining popularity in the United States because of the increased barrel life and outstanding accuracy of a hammer forged barrel. The BCM BFHâ„¢ series of barrels are made right here in the USA! (Just like all the BCM products.)