I'll be go to hell! Someone followed directions!
Get a 5/8ths inch dowell and tap it.
You may have to reassemble the Magazine cap and spring. Do not put the dowell back in. Use the pin to rotate the magazine 90 degrees and it will then lift up about two inches and then you can rotate the barrel 90 degrees and lift the barrel off the receiver.
Set the magazine cap on the edge of the workbench for support and tap gently with a short piece of dowell. The follower is cocked in the tube. Once you move it a little it will be free. Chances are good the magazine follower (the stuck part) is also rusted in place. It probable got stuck because someone used a piece of dowell for a plug. You need a cap at the top end to keep it from sliding down into the follower.
The shell stop is a little lever inside the receiver that has a round knob on the backside and it toggles up and down a little as the action works back and forth. It stops the shells from coming out of the magazine when the action is shut.
If it is rusted clean the follower up with WD-40 and steel wool. Wrap a 16 gauge brush in fine steel wool, chuck it in a drill and use WD-40 to clean up the inside of the tube.
