A5 Only Shoots at 210fps

Everything is sealed nicely on the gun, oiled up with new orings.  But for whatever reason I'm not getting enough pressure to get the balls up to 280.  It consistently shoots at 210fps even when i adjust the velocity screw. 

I have a 20oz CO2 tanks with a 32 degree remote line, on an A5A2 airthrough stock system.

Thanks for all the help. 

Velocity adjuster on stock maybe?

Ball dent is not in backwards, I've tryied with the v-screw all the way in and out, we had just filled the tank when I tried chronoing it, I also tried after playing a few games to see if anything changed.  I tried using the stock barrel and the flatline to see if it was the barrel.

We used the chrono to setup everyone elses gun that day and there's seemed fine.  I even tried my back up 9oz tank thinking it was the tank.  The thing that gets me is that my response trigger stopped working also, when I fully close it, the trigger gets hard to press but not as much as it should.  The cyclone works, but I have had the ocassional shot where no ball comes out (miss fire).

The last thing I can think of is to replace all the small parts such as the springs, etc.

Im going to take apart the trigger system and see if something there is affecting it.

Thanks for your replies.

The A5A2 gas-through stock does not have an RVA, so that wouldn't do anything.

I bet what you will have to do is stretch out the drive spring by pulling gently on both ends.  This will lengthen it a bit.  You don't want to pull too much that you deform it in any way, though, so be a bit careful.  If you don't want to do that, take a BB and put it in the stock where the drive spring sits when the marker is assembled.  This will give you a bit of a boost.

Or, get a Madmann spring kit

jj