You have to remove the meprolight sight.
Tools needed should be : Multi-bit screwdriver kit (I can't remember the size needed), a tavor barrel wrench and a pointed punch
-You start by removing the two hex screws at the front of the handguard and you remove it.
-Remove the little cotter pin on the right side of the front sling swivel, watch out, It flies!!
-Unscrew the front sling swivel and take out the two parts.
-Remove the top, its a tricky part, if I remember you have to move the plastic cover at the front before you can actually move the charging handle over some metal stopper.
-Now use the punch on the barrel lock on the left side of the rifle, its a small round metal part, when pushed on, a part of it will swivel. Make sure you can see its tip underside.
-While doing so, use your barrel wrench in the slot on right side and turn it until it face the white mark.
-Pull the barrel out, just make sure the gas cylinder and the charging handle guide stays in the receiver, they might come out when you take off the barrel.
-Now unscrew the two bolts at the base of the M-21 sight, put on your brand new rail.
-Reassemble by reversing the process described
-Install some bad ass optics
-Take some pictures and post them here
