Help with talon ss shooting slow and reg setup

[22Talon]

Needing help from any talon experts here.

Ok I have been trying to get my Talon SS back in order and got an altaros reg, hammer, breech, new seals etc from talon tunes.

Putting it together was a bit of a pain as its the first gen so a lot of stuff is a bit different and not much guides for it.

Anyway it shoots, very consistent but at max power wheel of 12 and top had open to full 2.5 turns, velocity is only 690 with jsb 18 grn pellets which to me seems slow .

Reg is set at 150 bar, wondering if that is too high and causing top hat to close to fast? Do i need to lower reg down a bit maybe? Also how can i empty tank fast without damging reg? Altaros said shoot the gun empty but that would take a long time.

The only other thing i noticed is the new plastic male screw part of the power wheel is a lot shorter than the old style originally on the gun(needed repayment as it cracked when I stripped the original screw years ago) could that casue it? Maybe get a stronger and longer spring?

 Im hoping the reg still let's me get orignal power of 25 or so fpe of possible.