Tuning/regulating an AT44

I purchased a new Hatsan AT44 QE short in .22 a couple of months ago. So far, the gun has been a winner.

But in factory trim it shoots too hard. I hunt on land that requires use of non-lead pellets and those (H&N Barracuda Green 12.35gr) were zinging at 1100fps out of the box. At that speed, accuracy was fair.

To get the FPS down into the low 900s, I adjusted the power as low as it would go by turning the power adjuster full clockwise.

Problem is that with the power turned down, I get a shot string with velocity steadily rising with each shot from 1 to 35. The FPS spread from min to max is about 120fps.

I'm no PCP expert, but my assumption is that I'm suffering from valve lock by turning down the impact force of the hammer.

My goal is to achieve a power level of about 23-25fpe with as flat a shot string as possible. I realize that is a relatively low power level for the AT44. Shot could is less important because this gun is primarily a hunter. 25-30 is more than enough.

I have an Audrius regulator for my AT44 and I'm curious if I could achieve my goals by leaving the power adjusted in the low setting, and installing the regulator adjusted to operate at a relatively low pressure. I think it comes pre-set at 130 bar. So maybe something like 100 or 110?

Any input or suggestions would be appreciated.

Thanks
R