This Instructable will walk you through the steps of disassembling a Mossberg Pump-action shotgun (models 500, 505, 535). Disassembling a Mossberg 500 shotgun can be learned and mastered quickly. It only takes a couple of minutes to disassemble, even if it is your first time attempting this task. The only tool required is a punch or something similar (small screwdriver, Allen wrench, or even a pen). With the shotgun disassembled, its parts can be thoroughly cleaned and inspected. This will keep your shotgun in top working condition, even in harsh environments.
These instructions break the shotgun down into 10 parts. Move your cursor over the parts on image of the disassembled shotgun to see the names of the parts.
Note: You should be familiar with the operations of the shotgun (i.e. Loading and unloading) before undertaking this task.
Source: www.instructables.com