Been a long time since I messed with one but the picture is showing the magazine release which should not have to be removed to get the barreled receiver out of the stock. I think there is a action screw hidden underneath the trigger plate so trigger plate first and then the action screws. If you decide to remove the spanner nut a wrench can be made out of tubing the size of the outer diameter of the nut with a hole in the tubing large enough to encapsilate(sp) the magazine button, then remove the metal from the tubing the depth and width of the spanner slots and drill a hole in the other end for a screwdriver to used as a handle. Good luck.
