Ebay find. Minimag valve s/n mm16811

On compressed air, 900 psi output
Brand new oring kit replace all orings and oiled
leaks out the bolt
pull the trigger and not full fire (more like a chirp)
increase the velocity and leaks out the back of the reg but fires better but not consistant
hold the trigger down and no leaks

any suggestions?

should I replace the spring pack or reg pin/spring?