Introduction: PVC Air Gun 1.0 Cal
The total cost for it was about $40
It uses a twin valve mechanism so it can store up to 12 shots without me having to refill the air in it (it has a small compressor mounted on it not pictured)
It shoots anything you can fit down the 1 inch barrel.
It holds up to 220 PSI but I usually store 80 PSI in it to avoid damage to the seals