I built this in layers so it should be easy to follow the instructions
if you have some knowledge of knex.
1. This gun.
2. Original gun
3. New pump
I recommend that you keep a Grey with you when you are using this gun. To clear Jams just pul back the firing pin and push the Grey down the barrel to push the red back in place, then pull the Grey out.
You can make the mag a large as you want just extend the top.
You might want to make the next version depending on what you use it for. instructables.com/id/My-Pump-Action-Shotgun-V37/
Step 1: Making the Handle
Step 2: Making the Body
2-3. Build this also.I just couldn't be bothered to take it apart.
Nothing much else to say. just look at the pictures.
The last pic is of the pump mech.