Had this problem, I just bought a TiPX with all the mags and mag holders and all the cool stuff. Took the TiPX to a big game. So stoked to use it, I wasn't a fan of 12 grams at the time so I was using it with a remote on HPA.
Same deal, 240 was about the highest I was getting. Wasn't very happy at all, just dropped $250+ on all this stuff and I couldn't use HPA. It stayed in the gearbag the entire weekend of the big game, or in the hands of other players. Couldn't even stand to look at the thing
On the bright side, this gun was probably the thing that brought me over to playing paintball with 12 grams, but the TiPX was still kind of a headache for me at first. I think Tippmann needs to sell each constant air kit with a warning about running HPA, I felt really cheated when I found out about this quirk.