Huntsman regal xl HR .22

Just got a Huntsman .22 40 ftlb with 18 shots.

In order to make it realistic, I reduced the preload of HST and the gun came to 30 ftlb where I wanted it to be.

But the number of shots are around 30 while I was expecting at least 40 shots.

Should I try to play with the striker travel by means of travel adjuster?

Anyone can help me making it efficient?

Regards, 

Umair Bhaur