Tuning FX impact hammer spring issue

Hey guys. Needed some help. Something weird is happening with my impact. Got an impact with the power plenum. Here is what’s happening. 


The gun came factory set at 130 bar which was too high. I lowered it down to 80 bar which is clearly giving me the speed I want. Am getting 930 with the 18 grains which is perfect. Everything is perfect. The accuracy is also super.

Only problem is that my hammer spring wheel doesn’t seems to work OR actually works in reverse. !!! 

If I keep the wheel at Min, I get 930 FPS. If I take it to Max, it goes down to 920. It stays at 930 FPS at any of the 1-5 numbers or the A-E markings. It only goes down to 920 when I keep the wheel at Max

The gun is much louder at Max but delivers lower speed. It’s quieter at Min and delivers higher speed. I took the wheel out as well thinking maybe it’s a wheel problem. But the cam inside is fine.

I tried to lower the Reg further down. Lowering the Reg reduced the FPS. I felt the hammer wheel would work now as it’s supposed to. But even at a lower Reg pressure the hammer wheel is giving me higher FPS at Min setting and Lower FPS at Max with hardly any variations in setting between the 2 extremes. Between Min and Max there is only a 20 FPS difference which doesn’t feel right. 

I don’t have any accuracy problems or any consistency problems. Chrony strings are great. Std dev is 3, spread is around 11. But the hammer wheel isn’t doing what it’s supposed to do. It’s like having a hammer wheel which doesn’t work.

Any idea what could be causing this ? 



Much thanks in advance.