Mossberg 500 Disassembly & Reassembly Video
An anonymous comment to an older post and video about the Mossberg 500 mentioned another youtube video that covers disassembly and reassembly of this popular shotgun. It can be a little tricky, but this video shows clearly how to do it.
If you have any trouble viewing the video, then here's a link to the video at youtube you can try.
Thanks to the commenter for pointing out this video!