If a new PCP will not hold air and you can hear air leaking from the barrel or fill port during the initial filling, follow these steps to troubleshoot your rifle.
- Cock the rifle before filling - this allows the firing valve to close.
If you are pumping with a handpump, pump quickly to build enough pressure and snap the firing valve closed. When there is enough pressure behind the valve, it will remain closed.
- Resume filling the rifle.
As long the tank retains enough pressure to keep the firing valve closed, your rifle will not leak.