Vulcan Gen 4 .25

[Nutcracker]

On the Vulcan Gen 4 .25, what is the factory reg  pressure in .25 cal set at.    Has anyone put a huma reg in theirs   and increased the FPS.  Currently  shooting at 890 with 25 grains I would like a little more maybe 920 .  Adjusting the hammer spring does not increase it any at all, first PCP I had that hammers spring does not increase ft pounds.  I have the rest of my .25 cals shooting 920 plus  and they are still accurate.  I am not concerned about shot count at all, so if that suffers not a concern.