It's pretty solid. Mounts in the rear iron sight cradle and screws into the stock. I really like this mount because I can also put a brass deflector on it.
I believe that's a magpull muzzle break. It's was $20 at the gun show.
Just to be clear its not integrated into the dust cover. I have a stock dust cover in there, the rail system mounts in the rear iron sight cradle and screws into the stock. I'm sure with some engineering you can make a quick release bolt in lieu of the rear mount screw. This way you can quickly tilt the rail up and take off the dust cover for clearing and/or cleaning.