I recently posted a message about my A-5.  I was having a problem with the pressure dropping and only allowing my gun to shoot about 230-250fps.  I would disconnect the remote and plug in the CO2 directly and I would be well above 300.  I spent a week trying to figure out what was wrong and had many suggestions from everyone here.  Thanks for your help. 

 The quick disconnect adapter that screws into the asa on the
grip is actually a little too long.  If you look into the asa, the hole
above the pin sits along the outer edge of the asa (because the pin for the co2 is in the middle).  The quick disconnect adapter screws into the asa too far and actually covers most of the air hole that leads into the gun.  I put an O-ring in there (the same one that goes on the CO2 tank) to allow some space between the asa and the quick disconnect adapter that screws in.  After I did this, I chronoed the gun and was easily shooting above 330 fps.  I turned the velocity adjuster back down to about 275 and haven't had a problem since.  I played for 6 hours on Saturday and everything worked well.

Sometimes the solution is just that simple.