Loosing air through the Barrel can happen if the hammer isn´t cocked, cause he pushes a Little bit on the valve pin + low pressure inside the valve it´s alot easier for the hammer to push the pin.
The langer tank was screwed in right ?
If the ASA pin has no contact to the pin in the middle your tank it wont open to release gas, also it can happen if you screw the tank to loose on marker that you will have a low airflow so on high fire rates the pressure will get down.
If you hear that air goes in the marker, than give a 1/4 to 1/2 turn extra to open the reg valve complete !!!
Sounds like an empty tank !!!