Welcome to A5OG!

Did the problems start when you installed the new powertube? Did it do this before? Are you using HPA or CO2? I had the same issue with my A5. It can be the older style rear bolt and valve. I called Tippmann and they replaced mine with the new style X7 rear bolt and valve. It has to do with the way the valve is made. There is some different milling to the new valve. If I used CO2, I was OK but when I used HPA, I had the low velocity issue.

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