The screws and the base itself are epoxied to the receiver. They cannot be removed without application of heat in my experience. Not heating will result in broken off screws or even a bent rail as you try to pry it off. Ask me how I know.
The front screw is positively for a mirage shield. Attempts to screw it in further can also result in a bent rail.
You will also notice that the rail has a pressed in dowel pin that interfaces with the reciever, a nice touch. That rail is screwed, glued and pinned. It's not moving.
Last edited by Tennessee; 11/26/14.
