Vitran Airsoft Shotgun (WIP-FAILURE)

I wanted to make a shotgun that acts like an airsoft 40mm shell. This gun was a prototype and does not work. I was thinking of putting a shell and blast air from behind to make it akin to a 40mm but make this more of a semi-auto or full-auto gun. Loading 40mm shells takes a while and this was to ‘solve’ it.

Some parts used inside are listed below

• 3/2 push button valve from Humphrey
• 5/2 push button valve from Humphrey
• 17mm diameter, 1mm wall, 500mm long stainless steel tube
• 10mm diameter, 10mm stroke dual acting cylinder
• 10mm diameter, 15mm stroke dual acting cylinder
• 10mm diameter, 10mm stroke, spring retract cylinder
• U-Cup seals (see model)
• ½" chrome plated shafting
• barb fittings
• Festo miniature inline pressure regulator
• 3mm diameter, 24mm long dowel pins
• 4 and 5mm screws
• ¼" push pins

Why did it not work:
The pressure was way way lower than expected. I ran this at 90psi, but it needs to be in the 180-240psi range akin to what 40mm shells use. I had falsely thought the amount of air I had was enough.
The amount of BBs being fired was way too much and they just kind of fell to the ground.

How does it work:

1. The shell is put in front of the air chamber.
2. Pulling the trigger opens a door at the front of the shell. Without this door the BBs would fall out of the barrel.
3. A valve at the top of the door is pressed, triggering the firing of the gun. The fire cylinder is retracted
4. Air is pushed into the shell and the BBs are fired
5. Releasing the trigger causes the air chamber to retract. The current shell is shifted to the side and a new shell is loaded and is ready to fire again

I would not suggest anyone build this gun and the gun I do have is going to be kept as a prototype but it isn't useful. Though, it does 'work'.