The valve had very few pieces in it, I'm wondering if something is missing from it. It's the older style valve so it's different than is in any of the videos on youtube. there's basically just the piercing pin and a spring and then the valve stem and that's it. one 0 ring goes between the two halves of the valve and one 0-ring goes in a groove on the outside of the valve.
Just to verify though, when I put a new co2 cart in, cock and pull the trigger and co2 just starts pouring out. If I cock and pull the trigger again before the co2 is gone it shoots but sounds like studder shot, like multiple blasts of air, sounds like badadada instead of a single pop. I guess that's because the valve stem/seal doesn't close back after the shot.