This gas block replaces your existing front sight to provide a simple,
low profile design that can be used to mount a rifle length forearm to a
carbine length barrel. It is mounted by the use of two set
screws (YHM-9383) and is .950 Inches
long. Manufactured from high quality steel and finished with a mil.
spec. phosphate coating. Made in the U.S.A. This gas block has a bore
diameter of .750 inches.