FX FX impact regulator in Panthera

Will the Fx impact regulator fit in the Panthera? I installed the extra high pressure Huma regulator and the recharge is very fast. The issue is the regulator drops in pressure over a period of time after shots and can’t hold the set pressure. For example I set the reg to 155bar and after a couple magazines it is at 152 bar with 170bar left on the fill. The stock regulator re charge was extremely slow but eventually got to set pressure. The stock regulator eventually creeped about eight bars higher then held that pressure. My idea was to get the impact high pressure regulator vs extra high so it had a bit softer springs to help the regulator recharge to my set pressure.
 
Have you verified the accuracy of your bottle gauge?
I just got done goin g through a friends Impact. The initial tune was shooting well, the gun sounded good but it was eating air like crazy.
Hmmmmmmm?
Next fill off my bottle and I watched the bottle gauge rather than the gun’s gauge. 30 bar low. I was effectively filling the gun to 220 bar.
May not be the problem but worth a look to eliminate the easy stuff
 
I have a sekhmet digital gauge for the reg and put a new gauge for bottle pressure. I assume the extra high pressure Belleville washers make it hard for the regulator to style in when getting close to set pressure. With a fresh fill, the gun will get about 8 shots on set pressure then has a hard time keeping the set pressure. I run a dual bottle with 700cc front bottle and stock 300cc rear.
 
3-4 bar drop till it is off the reg as well. If it sits over night, the pressure goes back to set pressure. I was thinking of putting softer spring to help get back to pressure
Finally got a response from HUMA. They say the 3 bar swing is normal with the small piston design and if you have it turned correctly, it won't effect the fps. There was no mention of changing out the springs to eliminate this.