PRI Gas Block for AR15, M16, M4, M4A1, for .750 barrels.  Same plane as flat top upper receiver !!

 

This Barrel mounted gas block has a 2 1/2" top rail same plain as the reciever. The rail is constructed of light wait hard coat aluminum. This gas block weights 2.5oz. Gas block fits over a .750 diameter barrel. Block locks into place with 2 crossbolts the same as the original PRI gas block front sight.

 

This gas block is compatible with the use of a milspec rear sights and the following RAIL MOUNT front sights: PRI, Troy Ind, BCM/Troy, MI-FFR, MBUS