IIRC, it is pretty much like most pump shotguns. Remove the trigger guard screw (from the left) and then drive out the trigger guard pin at the front of the trigger guard. That should let the trigger guard come free of the receiver. I recommend removing the buttstock before working on the trigger group as it is a PITA due to the weight. Unscrew the butt plate (or pad) and use a long screwdriver to remove the butt stock bolt. Be careful re-installing the bolt, though. It goes into the alloy trigger guard and if cross threaded or the guard threads are stripped, a new trigger guard will be needed, and they may or may not be available from Gun Parts and will be expensive.
There are a couple of tricky places inside, one is the release spring, an oddly shaped piece of spring wire that is often the victim of amateur work, and the shell stop screw and nut which have to allow the shell stop to pivot but not unscrew.
Once the trigger group is out, removal of the bolt is straight-forward.
Jim
