Did a little adjusting to my hatsan Vectis today, reduced hammer spring tension by a couple turns. I took 48 shots using JSB 18.13g, I got 31 shots before pressure started dropping pretty rapidly, my average was 840fps 28ft lbs. From 200 bar I dropped 100 bar over the 48 shots and a little over 50 bar for the 31. I tired multiple adjustments to the hammer spring but I feel this gave me the best results with shot count compared to power. 