This 16” pencil barrel is perfect for replacing an old, worn barrel or upgrading your current rifle build. It is configured with a 1913 Mil Std. railed gas block for mounting your choice of front sight options. The pencil build is straight from the chamber to the threaded muzzle with a .625” diameter at the gas block location. It is machined from 4150 chrome moly Vanadium 11595E steel, has a Melonite QPQ finish inside and out and a 1 in 9” right hand twist. This sub-assembly includes the barrel with M4 feed ramps, 1913 Mil Std. gas block (installed with swivel and rivet), barrel nut, handguard cap and threaded 1/2″ x 28 T.P.I. muzzle.