This gas block replaces your existing front sight and allows the user to
mount accessories to its two picatinny rails. This gas block allows the
mounting of our forearms without the removal of your muzzle accessory.
Purchase our gas block mounted flip front sight (YHM-9584) or our solid
front sight (YHM-9495) to retain your iron sights. It is mounted by the
use of four socket head cap screws using a 7/64″ Allen wrench. This gas
block has a bore diameter of .750 inches. Made from high quality steel
and finished with a Mil. Spec. phosphate coating.