Good job.
Man I bet those marble get going fast in 5ft of barrel. You should paint fish on it and give it a name.

Clean and simple, good job.

Eat Beans, use Methane...

I woke up this morning and there was a carrot in the back of my truck

That will work at lower pressures, higher pressures will shred the foam. good luck.

I plan on using 1'' high pressure gas pipe capable of 2000 psi. I wont be firing a hole tank full at a time, just the 5 to 6 inches of behind the solenoid will be pressurized. As for dump time with a 1/2'' barrel its gonna be pretty quick, but with the .177 rifled barrel i would have several seconds...

Well basically 200 psi isn't enough for me so I'm gonna kick it up a notch with compressed Oxygen. This beast will be made of PG&E high-pressure gas pipe so it handle the extreme pressures. I will be using a high-pressure solenoid for quick opening, burst disks would not be economical seeing they ne...