How to Disassemble a Mossberg 500 Series Shotgun

Picture of How to Disassemble a Mossberg 500 Series Shotgun
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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.
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Step 1: Clear the shotgun

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Danger: Safety is essential when working with any firearm and ensuring the shotgun is unloaded is a necessary step before beginning disassembly.

1. Make sure the safety is on (safety button pushed reward with no red dot showing)

2. Check the magazine tube to ensure it is clear of any shells

3. Open the Action

a. Depress action lock lever

b. Pull rearward on the forearm

4. Check the chamber area to ensure it is clear of any shells

The shotgun is now clear and it is safe to begin disassembly.

Step 2: Remove the Barrel

Picture of Remove the Barrel
1. Open the action halfway

2. Unscrew (counter-clockwise) the takedown screw

3. Pull forward on the barrel

Note: The Mossberg 500 comes with interchangeable barrels allowing the operator to switch to a barrel that better suits their intended uses. To change barrels simply remove the barrel that is to be changed and attach the desired barrel.

Danger: Barrels of different models and calibers should not be interchanged. This can cause serious malfunctions in the firearm’s operation endangering the operator and those nearby.

Step 3: Remove the Trigger Group

Picture of Remove the Trigger Group
This is the only step requiring the use of a tool (punch, small screwdriver, Allen wrench, etc...)

1. Push the trigger housing pin completely out of the shotgun

2. Pull down on the rear of the trigger guard

Caution: Do not pull the trigger when the trigger assembly is out of the shotgun because it may damage the part.

Caution: The Trigger housing pin is very small and has a tendency to roll. Put it in a place where you can easily keep track of it so it does not become lost.

Step 4: Remove the Cartridge Stop and the Cartridge Interrupter

Picture of Remove the Cartridge Stop and the Cartridge Interrupter
The cartridge stop and cartridge interrupter are held in place only by the trigger group. With the trigger group removed, they are free to fall out of place.

Pull the cartridge interrupter and cartridge stop out of the receiver.

Note: The cartridge interrupter and cartridge stop fit only in their intended side so keeping track of which piece came from which side in not necessary.

Step 5: Remove the Bolt Slide

Picture of Remove the Bolt Slide
Pull the bolt slide down and out of the bottom of the receiver

Tip: If the forearm has not been moved the bolt slide should be lined up correctly for easy removal.

Tip: If the bolt slide does not come out easily then use the forearm to position the bolt slide directly below the relief cuts in the receiver (about halfway back).

Step 6: Remove the Forearm

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Push the forearm forward

Step 7: Remove the Bolt

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Use your finger to push the bolt forward and out of the circular hole where the barrel used to be.

Step 8: Remove the Elevator

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1. Swing the sliver, forward end of the elevator down and out of the receiver

2. Squeeze the arms together and pull forward out of the bottom of the receiver

Tip: The safety on the receive must be in the safe position to remove the cartridge elevator.

Step 9: Finished/ More resources

Picture of Finished/ More resources
The shotgun is now disassembled and it can be thoroughly cleaned and inspected. This will keep it in top working condition and improve the life of your shotgun.

Owner's Manual

Video instructions
Having owned one of these for many years, and knowing how easy it is to do, I must ask; Is there a specific reason you did not remove the magazine?
Your tutorial worked like a champ, it took all the guess work out. I was able to disassemble in less then 10 minutes give or a take a few. Thanks again.
Great detailed breakdown, good work!
zazenergy3 years ago
Awesome! Thank you for showing how to safely work with this weapon.