That's a 6" chamber, and he said he used 90PSI.
Most of the time 90 psi is more than enough.
Looking at my pic I could easily shoot a spud all the way to the treeline with 90psi.
The highest Ive gotten my gun to was 120 psi and the potato was in pieces before it reached the end of the barrel.
Note: Overall the gun is safe. I insist on wearing a hoody, safety glasses, ear plugs and heavy pants when using it. The shrapnel can hurt.













